Undefined characters for x86_64 architecture in QT creator

I'm just starting out with C ++ and learning how to use the QT creator as an IDE, so I suspect it might be very simple, but I might miss something. I installed apollo MQ and installed apache CMS ( C ++ messaging service ) so that I can interact with the server in C ++. The problem is that I don't know what I'm doing :-) (for now), and I'm not sure why I am getting the above error when using examples.

I am sure that the examples are good because they are included in the folder with the original example, so I suspect that the configuration of the project is incorrect (since this is the only value that I really affect).

Here is the .pro file:

TEMPLATE = app
CONFIG += console
CONFIG -= qt

SOURCES += main.cpp

INCLUDEPATH += /usr/local/include/activemq-cpp-3.4.2/
INCLUDEPATH += /opt/local/lib/

Here is the contents of the folder I'm pointing to (the files I want are inside subdirectories):

drwxr-xr-x  13 root  admin   442 May 11 19:09 activemq
drwxr-xr-x  48 root  admin  1632 May 11 19:09 cms
drwxr-xr-x   9 root  admin   306 May 11 19:09 decaf

Here is the error I get:

20:54:22: Running build steps for project stackexchangeexample...
20:54:22: Configuration unchanged, skipping qmake step.
20:54:22: Starting: "/usr/bin/make" -w
make: Entering directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
/Users/lostsoul/QtSDK/Desktop/Qt/4.8.1/gcc/bin/qmake -spec ../../../QtSDK/Desktop/Qt/4.8.1/gcc/mkspecs/macx-g++ CONFIG+=declarative_debug -o Makefile ../stackexchangeexample/stackexchangeexample.pro
make: Leaving directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
make: Entering directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
g++ -headerpad_max_install_names -arch x86_64 -Xarch_x86_64 -mmacosx-version-min=10.5 -o stackexchangeexample.app/Contents/MacOS/stackexchangeexample main.o      
Undefined symbols for architecture x86_64:
  "activemq::library::ActiveMQCPP::initializeLibrary()", referenced from:
      _main in main.o
  "activemq::library::ActiveMQCPP::shutdownLibrary()", referenced from:
      _main in main.o
  "activemq::core::ActiveMQConnectionFactory::ActiveMQConnectionFactory(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)", referenced from:
      SimpleProducer::run()      in main.o
  "cms::CMSException::CMSException(cms::CMSException const&)", referenced from:
      SimpleProducer::run()      in main.o
  "typeinfo for cms::CMSException", referenced from:
      GCC_except_table15 in main.o
      GCC_except_table16 in main.o
      SimpleProducer::run()      in main.o
  "cms::CMSException::~CMSException()", referenced from:
      SimpleProducer::run()      in main.o
  "decaf::lang::Thread::getId()", referenced from:
      SimpleProducer::run()      in main.o
  "decaf::lang::Long::toString(long long)", referenced from:
      SimpleProducer::run()      in main.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
make: *** [stackexchangeexample.app/Contents/MacOS/stackexchangeexample] Error 1
make: Leaving directory `/Users/lostsoul/Dropbox/qt_cuda/stackexchangeexample-build-desktop-Desktop_Qt_4_8_1_for_GCC__Qt_SDK__Debug'
20:54:22: The process "/usr/bin/make" exited with code 2.
Error while building project stackexchangeexample (target: Desktop)
When executing build step 'Make'

and if that helps, here is the code I'm running (it may not be useful to anyone for help, because you need to install a bunch of things to make it work, but just in case it helps):

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <decaf/lang/Thread.h>
#include <decaf/lang/Runnable.h>
#include <decaf/util/concurrent/CountDownLatch.h>
#include <decaf/lang/Long.h>
#include <decaf/util/Date.h>
#include <activemq/core/ActiveMQConnectionFactory.h>
#include <activemq/util/Config.h>
#include <activemq/library/ActiveMQCPP.h>
#include <cms/Connection.h>
#include <cms/Session.h>
#include <cms/TextMessage.h>
#include <cms/BytesMessage.h>
#include <cms/MapMessage.h>
#include <cms/ExceptionListener.h>
#include <cms/MessageListener.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <memory>

using namespace activemq;
using namespace activemq::core;
using namespace decaf;
using namespace decaf::lang;
using namespace decaf::util;
using namespace decaf::util::concurrent;
using namespace cms;
using namespace std;

////////////////////////////////////////////////////////////////////////////////
class SimpleProducer : public Runnable {
private:

    Connection* connection;
    Session* session;
    Destination* destination;
    MessageProducer* producer;
    bool useTopic;
    bool clientAck;
    unsigned int numMessages;
    std::string brokerURI;
    std::string destURI;

private:

    SimpleProducer( const SimpleProducer& );
    SimpleProducer& operator= ( const SimpleProducer& );

public:

    SimpleProducer( const std::string& brokerURI, unsigned int numMessages,
                    const std::string& destURI, bool useTopic = false, bool clientAck = false ) :
        connection(NULL),
        session(NULL),
        destination(NULL),
        producer(NULL),
        useTopic(useTopic),
        clientAck(clientAck),
        numMessages(numMessages),
        brokerURI(brokerURI),
        destURI(destURI) {
    }

    virtual ~SimpleProducer(){
        cleanup();
    }

    void close() {
        this->cleanup();
    }

    virtual void run() {
        try {

            // Create a ConnectionFactory
            auto_ptr<ActiveMQConnectionFactory> connectionFactory(
                new ActiveMQConnectionFactory( brokerURI ) );

            // Create a Connection
            try{
                connection = connectionFactory->createConnection();
                connection->start();
            } catch( CMSException& e ) {
                e.printStackTrace();
                throw e;
            }

            // Create a Session
            if( clientAck ) {
                session = connection->createSession( Session::CLIENT_ACKNOWLEDGE );
            } else {
                session = connection->createSession( Session::AUTO_ACKNOWLEDGE );
            }

            // Create the destination (Topic or Queue)
            if( useTopic ) {
                destination = session->createTopic( destURI );
            } else {
                destination = session->createQueue( destURI );
            }

            // Create a MessageProducer from the Session to the Topic or Queue
            producer = session->createProducer( destination );
            producer->setDeliveryMode( DeliveryMode::NON_PERSISTENT );

            // Create the Thread Id String
            string threadIdStr = Long::toString( Thread::getId() );

            // Create a messages
            string text = (string)"Hello world! from thread " + threadIdStr;

            for( unsigned int ix=0; ix<numMessages; ++ix ){
                TextMessage* message = session->createTextMessage( text );

                message->setIntProperty( "Integer", ix );

                // Tell the producer to send the message
                printf( "Sent message #%d from thread %s\n", ix+1, threadIdStr.c_str() );
                producer->send( message );

                delete message;
            }

        }catch ( CMSException& e ) {
            e.printStackTrace();
        }
    }

private:

    void cleanup(){

        // Destroy resources.
        try{
            if( destination != NULL ) delete destination;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        destination = NULL;

        try{
            if( producer != NULL ) delete producer;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        producer = NULL;

        // Close open resources.
        try{
            if( session != NULL ) session->close();
            if( connection != NULL ) connection->close();
        }catch ( CMSException& e ) { e.printStackTrace(); }

        try{
            if( session != NULL ) delete session;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        session = NULL;

        try{
            if( connection != NULL ) delete connection;
        }catch ( CMSException& e ) { e.printStackTrace(); }
        connection = NULL;
    }
};

////////////////////////////////////////////////////////////////////////////////
int main(int argc AMQCPP_UNUSED, char* argv[] AMQCPP_UNUSED) {

    activemq::library::ActiveMQCPP::initializeLibrary();

    std::cout << "=====================================================\n";
    std::cout << "Starting the example:" << std::endl;
    std::cout << "-----------------------------------------------------\n";

    // Set the URI to point to the IPAddress of your broker.
    // add any optional params to the url to enable things like
    // tightMarshalling or tcp logging etc.  See the CMS web site for
    // a full list of configuration options.
    //
    //  http://activemq.apache.org/cms/
    //
    // Wire Format Options:
    // =====================
    // Use either stomp or openwire, the default ports are different for each
    //
    // Examples:
    //    tcp://127.0.0.1:61616                      default to openwire
    //    tcp://127.0.0.1:61616?wireFormat=openwire  same as above
    //    tcp://127.0.0.1:61613?wireFormat=stomp     use stomp instead
    //
    std::string brokerURI =
        "failover://(tcp://127.0.0.1:61616"
//        "?wireFormat=openwire"
//        "&connection.useAsyncSend=true"
//        "&transport.commandTracingEnabled=true"
//        "&transport.tcpTracingEnabled=true"
//        "&wireFormat.tightEncodingEnabled=true"
        ")";

    //============================================================
    // Total number of messages for this producer to send.
    //============================================================
    unsigned int numMessages = 2000;

    //============================================================
    // This is the Destination Name and URI options.  Use this to
    // customize where the Producer produces, to have the producer
    // use a topic or queue set the 'useTopics' flag.
    //============================================================
    std::string destURI = "TEST.FOO";

    //============================================================
    // set to true to use topics instead of queues
    // Note in the code above that this causes createTopic or
    // createQueue to be used in the producer.
    //============================================================
    bool useTopics = false;

    // Create the producer and run it.
    SimpleProducer producer( brokerURI, numMessages, destURI, useTopics );

    // Publish the given number of Messages
    producer.run();

    // Before exiting we ensure that all CMS resources are closed.
    producer.close();

    std::cout << "-----------------------------------------------------\n";
    std::cout << "Finished with the example." << std::endl;
    std::cout << "=====================================================\n";

    activemq::library::ActiveMQCPP::shutdownLibrary();
}

I just created an empty C ++ project, modified the .pro file to include the library path, and then copy / paste the code into main.cpp. Any idea what causes this? and how can i prevent this?