http://bugs.winehq.org/show_bug.cgi?id=17056
--- Comment #24 from Corey coreyhtml@gmail.com 2009-05-26 20:20:07 --- "When you get this error:
CAudioSourceMemWave (**.wav): GetDataPointer() failed.
Go to your voice options and unclick the 'boost microphone' go to servers and connect. Your in-game sound should work. You will have to do this everytime you start TF2, for some odd reason this option does not save. In fact, if your try to edit out the microphone settings in the config.cfg it will not fix the problem. Unchecking that box before starting a game seems to work if you join a server; it does not work if you try to start your own server. It's an extremely temperamental bug but this works well and you don't have to remove pulse audio to do it."
Posted by Ken on April 13th at http://appdb.winehq.org/objectManager.php?sClass=version&iId=9901
Works for me, but according to other comments, not for everyone.