http://bugs.winehq.org/show_bug.cgi?id=21436
--- Comment #2 from Jon z jzuckerman@gmail.com 2010-01-22 18:44:29 --- For what it's worth:
When I set my windows mode to "Windows Vista" in winecfg the problem went away. Setting the value back to "Windows 2008" or "Windows 7" did NOT reproduce the bug.
I have Steam installed on a windows 7 partition on the same computer and the bug never occurred there.