http://bugs.winehq.org/show_bug.cgi?id=23286
--- Comment #11 from 3vi1 winehq.org@eternaldusk.com 2010-08-23 09:56:21 --- (In reply to comment #10)
I'm getting this with L4D2 also. Usually it disconnects with pak01_dir.vpk not found, although I just experienced "Disconnected: Server unable to authenticate Steam ID" I'm on Debian with self-compiled 1.3 wine source.
I now believe the pak01_dir.vpk problem is unrelated. When Valve pushes out their mutations on Friday nights, the clients get updated but the servers are not rebooted immediately. So, the server/client really do have a mismatch (until the servers next reboot).
Good to know that I'm not the only one seeing the authentication problem - though I wish neither of us was.