It could be the sound card driver, since I couldn't find the original disc for the audigy card when I reinstalled. Tried downloading from creative.com but it just doesn't seem right, some software is missing.
Removing the custom sounds (Waffle's sound pack, whatever the latest version is) fixed the problem, and since 3 days AH is running fine.
I'll send you a dxdiag though skuzzy, thanks!