If this doesn't fix it for you, we should note your system in the release notes and ask for more input from people who run the development series. I'm doing serious work in there right now that may or may not resolve it for you, but I've completely rethought how it should look anyway. Also, I hope to re-enable the old sound code (for the most part), so you'll be able to compare it. But this is more long-term work, won't be done if we're going to do 0.3 anytime soon.
It could be a problem with sdl_mixer on your platform, or more likely how we're using it currently. Can you try Crimson Fields, if you have't already? I stole most of the initial batch of code I used from there...
