Java: JGraphT adds edges using a loop

Is it possible to add edges to a graph using a loop? I am parsing a string to determine the corresponding edges and labels. For some reason, it will only add an edge for the first round of the while loop used to iterate over String. For everyone else, the following message appears ...

Warning: the edge was deleted because the main graph JGraphT refused to create it. This situation can occur when the restriction of the base chart is violated, for example, an attempt to add a parallel edge or a custom loop to the chart that prohibits them. To avoid this message, be sure to use the appropriate JGraphT graph.

import java.awt.*;
import java.awt.geom.*;

import javax.swing.*;

import org.jgraph.*;
import org.jgraph.graph.*;

import org.jgrapht.*;
import org.jgrapht.ext.*;
import org.jgrapht.graph.*;

// resolve ambiguity
import org.jgrapht.graph.DefaultEdge;

public class JGraphAdapterDemo
    extends JApplet
{

    private static final long serialVersionUID = 3256444702936019250L;
    private static final Color DEFAULT_BG_COLOR = Color.decode("#FAFBFF");
    private static final Dimension DEFAULT_SIZE = new Dimension(530, 320);

    static ListenableGraph<String, String> g =
        new ListenableDirectedMultigraph<String, String>(String.class);

    static int [] finalStates = new int[10];
    static int startState = 0;
    static char tran = ' ';
    static int endState = 0;

    private JGraphModelAdapter<String,String> jgAdapter;

    public static void main(String [] args)
    {
        JGraphAdapterDemo applet = new JGraphAdapterDemo();
        applet.init();

        JFrame frame = new JFrame();
        frame.getContentPane().add(applet);
        frame.setTitle("JGraphT Adapter to JGraph Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    public void init()
    {
        // create a JGraphT graph
        ListenableGraph<String, String> g =
            new ListenableDirectedMultigraph<String, String>(String.class);

        // create a visualization using JGraph, via an adapter
        jgAdapter = new JGraphModelAdapter<String, String>(g);

        JGraph jgraph = new JGraph(jgAdapter);

        adjustDisplaySettings(jgraph);
        getContentPane().add(jgraph);
        resize(DEFAULT_SIZE);

        int numStates = 4;
        int numSymbols;
        int currentState;
        int i = 0;

            String input = "4 2 0 2 -1 0 a 1 1 b 3 2 c 2 3 c 3 -1";     //place input String here
            int readInt = 0;
            int j = 0;
            String str = "";
            int place = 0;
            String fState;

            //read in numStates, numSymbols, initialState
            i=0;

            //parse string 
            i = input.indexOf(" ",0);

            str = input.substring(0,i); //number of states
            numStates = Integer.parseInt(str);  //convert to int

            for(int k = 0; k< numStates; k++){
                g.addVertex("q"+k);
            }

            i++;
            j = i;

            i=input.indexOf(" ",j);

            str = input.substring(j,i); //number of symbols
            numSymbols = Integer.parseInt(str);

            i++;
            j = i;

            i=input.indexOf(" ",j);

            str = input.substring(j,i); //initial state
            currentState = Integer.parseInt(str);   

            i++;
            j = i;      

            //read in finalStates
            while(readInt!=-1){
                i=input.indexOf(" ",j);
                fState = input.substring(j,i);  //a final state
                readInt = Integer.parseInt(fState);
                if(readInt!=-1){
                    finalStates[place] = readInt;
                    i++;
                    j = i;
                    place++;
                }//end if
            }//end while
            i++;
            j = i;

            String sState;
            String eState;

            while(startState!=-1&& j<(input.length()-2)){           //until end of file
                i=input.indexOf(" ",j);
                sState = input.substring(j,i);  //start state
                startState = Integer.parseInt(sState);  //convert to int
                if(startState!=-1){             
                    i++;
                    j = i;

                    String cStr = "";
                    tran = input.charAt(i);         //transition
                    cStr = cStr + tran;
                    i = i+2;
                    j=i;        

                    i=input.indexOf(" ",j); 
                    eState = input.substring(j,i);      //end state
                    endState = Integer.parseInt(eState);

                    i++;
                    j=i;
                    String one = "q"+startState;
                    String two = "q"+endState;
                    System.out.println(one+ two +" "+cStr);
                    g.addEdge(one, two, cStr);

                    //drawEdge(one, two, cStr);

                }//end if

            }//end while

    }

    public static void drawEdge(String v, String v1, String label){
        System.out.println(v +" "+v1+ " "+label);
        g.addEdge(v,v1,label);
    }

    private void adjustDisplaySettings(JGraph jg)
    {
        jg.setPreferredSize(DEFAULT_SIZE);

        Color c = DEFAULT_BG_COLOR;
        String colorStr = null;

        try {
            colorStr = getParameter("bgcolor");
        } catch (Exception e) {
        }

        if (colorStr != null) {
            c = Color.decode(colorStr);
        }

        jg.setBackground(c);
    }

    @SuppressWarnings("unchecked") // FIXME hb 28-nov-05: See FIXME below
    private void positionVertexAt(Object vertex, int x, int y)
    {
        DefaultGraphCell cell = jgAdapter.getVertexCell(vertex);
        AttributeMap attr = cell.getAttributes();
        Rectangle2D bounds = GraphConstants.getBounds(attr);

        Rectangle2D newBounds =
            new Rectangle2D.Double(
                x,
                y,
                bounds.getWidth(),
                bounds.getHeight());

        GraphConstants.setBounds(attr, newBounds);

        // TODO: Clean up generics once JGraph goes generic
        AttributeMap cellAttr = new AttributeMap();
        cellAttr.put(cell, attr);
        jgAdapter.edit(cellAttr, null, null, null);
    }

    //~ Inner Classes ----------------------------------------------------------

    /**
     * a listenable directed multigraph that allows loops and parallel edges.
    // */
    private static class ListenableDirectedMultigraph<V, E>
    extends DefaultListenableGraph<V, E>
    implements DirectedGraph<V, E>
    {
    private static final long serialVersionUID = 1L;

    ListenableDirectedMultigraph(Class<E> edgeClass)
        {
        super(new DirectedMultigraph<V, E>(edgeClass));
        }
    }


}