Firmware upgrade causing application null pointer exceptions on 7650

[damien12345]

I am part of a team who have been developing a J2ME application for the 7650. The application was developed and tested entirely on 7650 phones with the 3.16 firmware. The application functions perfectly. It's non-network and runs entirely on the phone. For internationalisation reasons we arranged for some tests to be run by a company in Asia. The only difference between their phones and ours being they run 3.34 firmware. The application manages to load up a couple of splash screens but before it hits the main menu crashes with a null pointer exception error.
Does anyone have any idea what is going on, changes in firmware upgrade that may result in this, etc.

Failing this is anyone aware of any emulators that allow you to use different firmware versions?

thanks in advance

[damien12345]

There is no easy way to post a stack trace...as it is we don't even have a phone with the the correct firmware on it. The firmware on their phone is actually 4.34.
Only API is the nokia full screen api.
2 splash screens are being displayed after which the program hangs. (At this point it should be trying to load up the menu system) The screen blanks out. Upon pressing a key the null pointer exception pops up.
Am completely confused as to why it should run fine on one build and not on another!