Android - "your device is not compatible with this version"

I put the application in the playback store, and my friend who is running 4.1 (Nexus 7) received the following message when trying to install my application: "your device is not compatible with this version." Why did this happen? Please help me.

Manifeast file

< ?xml version="1.0" encoding="utf-8"?>

< manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.ibkr.pcg"
      android:versionCode="3"
      android:versionName="1.1">

< uses-sdk android:minSdkVersion="7"  
      android:targetSdkVersion="8"/>
<uses-permission android:name="android.permission.INTERNET"></uses-permission> 
<uses-permission android:name="android.permission.CAMERA" />        
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" ></uses-permission>  

<!-- C2DM Permissions Start -->
 <!-- Only this application can receive the messages and registration result --> 
<permission android:name="com.ibkr.pcg.permission.C2D_MESSAGE" android:protectionLevel="signature" />
<uses-permission android:name="com.ibkr.pcg.permission.C2D_MESSAGE" /> 

 <!-- This app has permission to register and receive message -->
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<!-- End of the C2DM Permissions -->

<application android:icon="@drawable/pcgicon" 
    android:label="@string/app_name" 
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen" 
    android:name="MyApplication"
    android:debuggable="true">
    <activity android:name=".PriceCheckGuruSplash"
              android:label="@string/app_name">      
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />    
        </intent-filter>  
    </activity>

     <!-- Only C2DM servers can send messages for the app. If permission is not set - any other app can generate it --> 
    <receiver
     android:name=".C2DMMessageReciever" android:permission="com.google.android.c2dm.permission.SEND" >
      <!-- Receive the actual message -->
     <intent-filter >
            <action android:name="com.google.android.c2dm.intent.RECEIVE" >  
            </action>
            <category android:name="com.ibkr.pcg" /> 
        </intent-filter>
    </receiver>

   <receiver
        android:name=".C2DMRegistrationReceiver"
        android:permission="com.google.android.c2dm.permission.SEND" >
        <intent-filter >
            <action android:name="com.google.android.c2dm.intent.REGISTRATION" >
            </action>
            <category android:name="com.ibkr.pcg" />
        </intent-filter>
    </receiver>

    <activity android:name="MessageReceivedActivty" android:screenOrientation="portrait"/>
    <activity android:name="LoginScreen" android:screenOrientation="portrait"> </activity>
    <activity android:name="RegistrationScreen" android:screenOrientation="portrait"> </activity>
    <activity android:name="ForgotPasswordScreen" android:screenOrientation="portrait"> </activity>
    <activity android:name="UserPreferences" android:screenOrientation="portrait"> </activity>
    <activity android:name="TrackedItems" android:screenOrientation="portrait"> </activity> 
    <activity android:name="WebPage" android:screenOrientation="portrait"> </activity>
    <activity android:name="CustomTabActivity" android:screenOrientation="portrait"> </activity>
    <activity android:name="TabGroup1Activity" android:screenOrientation="portrait"> </activity>
    <activity android:name="TabGroup2Activity" android:screenOrientation="portrait"> </activity>
    <activity android:name="TabGroup3Activity" android:screenOrientation="portrait"> </activity>
    <activity android:name="TabGroup4Activity" android:screenOrientation="portrait"> </activity>
    <activity android:name="SearchScreen" android:screenOrientation="portrait"> </activity>
    <activity android:name="SearchResultsScreen" android:screenOrientation="portrait"></activity>
    <activity android:name="ProductDisplay" android:screenOrientation="portrait"></activity>
    <activity android:name="VendorsDisplay" android:screenOrientation="portrait"></activity>
    <activity android:name="Filter" android:screenOrientation="portrait"></activity>
    <activity android:name="barcodeScanner" android:screenOrientation="portrait"></activity>
    <activity android:name="ScannerPage" android:screenOrientation="portrait"></activity> 
    <activity android:name="Linegraphpage" android:screenOrientation="landscape"></activity>        
    <activity android:name="org.achartengine.GraphicalActivity" android:screenOrientation="landscape"/> 
    <activity android:name="org.acra.CrashReportDialog"
    android:theme="@android:style/Theme.Dialog"
    android:launchMode="singleInstance"
    android:excludeFromRecents="true"
    android:finishOnTaskLaunch="true" />
</application>

</ Manifest>