http://bugs.winehq.org/show_bug.cgi?id=10947
--- Comment #6 from Brandon rbrandonstewart@yahoo.com 2008-01-13 09:17:14 --- Based on workarounds for similar bugs, I believe the following will work around the bug for TF2 users. In any case, I've done it and haven't had issues since.
In the directory .wine/drive_c/Program Files/Steam/steamapps/<account name>/team fortress 2/tf, create a file called motd_temp.html that's empty. Change it's owner to root and make it unreadable and unwriteable to anyone else.
Now when you connect to a server that has an HTML motd, it should just show a black box where the motd should be. But it won't crash.