(keitai-l) working on the emulator but not in the phone

Hello all, I have a problem: I have written an application and It is 
working on the emulator, but when I download it from the server to the 
phone, it says Application Error. I know it is not a problem of the 
download process or so, because a little part of the beginning of the 
application executes correctly.

Anyone can give any hint? thanks very much