http://bugs.winehq.org/show_bug.cgi?id=23516
--- Comment #8 from PLL pslla.dev@gmail.com 2010-10-26 12:55:38 CDT --- (In reply to comment #7)
Emulating a virtual desktop and playing the game fullscreen (instead of borderless window mode) fixed this problem for me.
I tried this a few times, the error stills happens everytime (play >30 minutes).
Seems like the bug where it can't authenticate the steam account is related to the sound droping, some times they have happened one following by the other.
I have noticed that if I keep constantly poking (say, each 5 minutes or so) the vpk files using snd_restart the bug is never activated.
It may be that the vpk files are being closed after a while and when l4d2 tries to load any sound or tries to validate the files, they are already closed and they can't be opened for some reason, which can be noticed in console where you find a lot of "not found" errors.
I am just speculating from my experience playing the game. Everything works great except for this tiny annoyance.