Well there're no third party apps on the device besides ours, and our application should be stable and pretty much bug-free by now. It has been in development for a long time and there are plenty of devices (7290, 8700, Pearls and 8800s), where it runs smoothly.
We even found an 8800 with the same RIM OS Version and no error occured. Which lets me think this might be BES specific, but why would it then work on the 8700s and not 8800s?
Don't know I'm starting to believe both 8800 devices are coincidencely broken somehow