When starting a game Steam throws an error saying The registry was in use by another process.
This seems due to a tendency of the steam client to crash when trying to shut down and release its registry. You can fix this problem by shutting down steam cleanly (keep running and exiting steam itself until you get a clean shutdown without any errors after "Shutting down" - watch the console you ran steam from) and then restarting it. Once steam has been shut down cleanly and restarted the error should not occur.
If all fails, start Steam, right-click on the game and select Properties. Go to Local files tab and click on Verify integrity of game cache...
http://appdb.winehq.org/appview.php?iVersionId=3731