ビルドはOKで、動作するとエラーが怒ってしまう。。。

↓　どんなエラーなんや？
startApp threw an Exception
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.String.substring(+45)
at GT1.mainF(+554)
at GT1.startApp(+11)
at javax.microedition.midlet.MIDletProxy.startApp(+7)
at com.sun.midp.midlet.Scheduler.schedule(+270)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+116)
Execution completed.
824461 bytecodes executed
35 thread switches
743 classes in the system (including system classes)
4240 dynamic objects allocated (129020 bytes)
3 garbage collections (95348 bytes collected)