A couple people have mentioned this problem going away after rebooting their computer.
If that doesn't help, try turning down (or even off) the hardware sound acceleration (Start | Run | type in 'dxdiag' and hit Enter, then switch to the Sound tab.
Not likely the problem, but try deleting all of the files in the '
..\Divine Divinity\Run\Dynamic' folder.
This folder is used as a cache for the game. Files are created / copied there from the save game folder when you load, and written / copied from that folder when you save a game. The files will be re-created as required the next time you start Divinity. If there was a corrupt file in that folder, deleting the files should fix the problem.
Troubleshooting Tips (& manual install procedure) 
