I try to write a simple MIDlet for my 6230i phone. The code runs well in the default color phone of the Sun made SDK, but it throws a ClassNotFound exception while starting if I try to run it on the "S40 SDK 6230i" or on the phone itself.

Here's a piece of the log:
Exception: java/lang/ClassNotFoundException
        at com.nokia.mid.impl.isa.ui.MIDletRTInfo.<init>(+120)
        at com.nokia.mid.impl.isa.ui.MIDletManager.loadMIDletSuite(+171)
        at com.nokia.mid.impl.isa.ui.MIDletManager.main(+71)
       Operands (1 items): 133fdb48,
I don't use any special API's, but I use "instanceof" operator in my code. Maybe this could cause this problem... I have no idea...

I can send my source code if anyone want to read it.

Thanks in advance!