After being opened for a while, DevCPU will close with the message "seg fault". I had it only twice so far and I haven't found out what was causing it yet.
I'm running a debian wheezy 32 bits (x86) with wmii.
As for precisions, it had been running for an hour or two when it occurred. I was starting/stopping the emulator quite a lot and saving/modifying files (cause we don't have a debugguer yet).