What is "Java error. Invalid format"?

I have made my own application in J2me to my mobile phone. The previous versions of this application works perfectly. But now (after a few changes in source code), when I c开发者_StackOverflowopy this appplication to my mobile phone (Smasung gt-s7550) I get: Java error. Invalid format and the application doesn't start. Do you know what it means?

invalid format can mean all kinds of different things. Without seeing any code, my guess would be a missing semi-colon or something to that effect.