Illegalthreadstate exception 110 Java ME

[Grimmjow]

I created a character that moves on a java midlet, the only thing is after about 10 seconds the character stops moving. I'm getting the following error when starting up:

Error:

Starting emulator in execution mode
Installing suite from: http://127.0.0.1:49690/Practicum_1.jad
[WARN] [rms     ] javacall_file_open: _wopen failed for: C:\Users\Bas\javame-sdk\3.0\work\0\appdb\_delete_notify.dat

TRACE: <at java.lang.IllegalThreadStateException: 110>, Exception caught in Display class
java.lang.IllegalThreadStateException: 110
java.lang.NullPointerException
        at org.netbeans.mobility.antext.StackTraceTranslator.getLineNumber(StackTraceTranslator.java:216)
        at org.netbeans.mobility.antext.StackTraceTranslator.translate(StackTraceTranslator.java:118)
        at org.netbeans.mobility.antext.RunTask$StackTraceTranslatorHandler$1.flush(RunTask.java:771)
        at org.netbeans.mobility.antext.RunTask$StackTraceTranslatorHandler$1.run(RunTask.java:817)
        at java.lang.Thread.run(Thread.java:619)

I have been looking on the internet to find a solution but I couldn't find any answers. Here's my Threads code:

    Thread frames = new Thread(new Runnable() {

        public void run() {

            while (true) {
                p1.beweegArmen();
                p1.verplaats();
                repaint();
                try {
                    Thread.sleep(300);
                } catch (InterruptedException ex) {
                    System.out.println("SHIT");

                } 
            }
        }
    });

Could anyone help on this?

Regards,
Grimmjow