http://bugs.winehq.org/show_bug.cgi?id=15263
--- Comment #28 from Kynan Rilee kynan.rilee@gmail.com 2009-02-06 11:04:44 --- Oh. Well, the title is "Cannot install games in Steam," so naturally, I assumed that meant "cannot INSTALL games in Steam" and not "cannot BUY games in Steam."
Trying to install a game in Steam does open a new window, but that is NOT an iexplore window. However, a number of people have been having the issue of "not being able to INSTALL games in Steam." So either what you are talking about is unrelated, or this bug is mistitled.
In any event, the people with my issue, the issue that actually does relate to the title, can solve it by reverting to older graphics drivers.