http://bugs.winehq.org/show_bug.cgi?id=31320
--- Comment #2 from GyB gyebro69@gmail.com 2012-07-25 12:44:32 CDT --- (In reply to comment #1)
Easy workaround: disable dwrite.dll in winecfg.
Just found out that there is a Steam command line parameter: '-no-dwrite', which makes it possible to start Steam. No idea what does that option do.