Everfades: are you playing with the patched exe? If that doesn't make a difference and it doesn't work on both versions of the exe, could you try disabling your Creative x-fi Titanium soundcard? (I.e. in the hardware manager. You can try with your onboard sound if you want to.)
Foulcrow: the only thing that was patched by the patch, was files: the EXE was patched and some data files. When you reinstalled, you overwrote those files, so the patch doesn't leave other "traces" of being patched. If you think it's the copy protection that's the culprit, you can try backing up the original divinity2.exe (in the bin folder), then patch, and then replace the new exe with the old one.
Do any of you see the SecuROM disc icon when it is checking the disc?
