imbaczek tracked this down to r4865 (thanks imbaczek!), which is the revision in which ogg/vorbis support was enabled.
So my hypothesis is that the Crystal Space ogg/vorbis DLLs possibly have some issue in their DLL initialization code.
However, I don't have really much time to investigate, so if anyone can figure this out many people would be very grateful. Cause if this can not be tracked down and fixed, it'll mean no music support in next version after all, which would kinda suck

Anyway, use this thread for centralized discussion on possible cause/fixes etc.
Original H&B threads:
http://spring.clan-sy.com/phpbb/viewtopic.php?t=12896
http://spring.clan-sy.com/phpbb/viewtopic.php?t=12864