Athlon64 3 GHz, ATi Radeon X300 SE, Windows Vista Ultimate 32-bit edition.
I tested with Catalyst 7.2, 7.3 and 7.4 (latest). Same issue. The sound drivers are up to date as well, although that doesn't mean they don't suck--Realtek AC 97 drivers suck regardless of version and OS.
I'll try to disable the sound and see if that solves it. I can create a minidump of the penumbra process when it freezes and upload it somewhere.
Finally, I tried attaching the VS debugger to the frozen process, and since I have Microsoft symbol server configured, I got semi-understandable callstack traces. There were several audio threads that appear to be working, a thread with SDL was Sleep'ing, and a rendering thread was stuck somewhere inside atioglxx.dll, which is obviously ATi's OpenGL driver. Pity I don't have symbols for that one
It seems like a dead-lock, although I can't tell the details. Again, a minidump would probably be helpful to you if you generate pdb's for release builds (which VS8 does by default, IIRC).