http://bugs.winehq.org/show_bug.cgi?id=23518
--- Comment #3 from Christopher Hotchkiss christopher.hotchkiss@gmail.com 2010-07-05 08:14:12 --- I am running an ext4 filesystem on Ubuntu 10.04. That file exists and I can cat it from another console session.
Also, I have successfully installed Steam in a different wine prefix just fine. I tested this wine prefix with a successful install of 7-zip.