http://bugs.winehq.org/show_bug.cgi?id=24172
--- Comment #3 from Vincent Povirk madewokherd@gmail.com 2010-09-12 17:20:48 CDT --- Yep, copying the contents of c:\windows\assembly\GAC_MSIL to c:\Program Files\Mono-2.6.7\lib\mono\gac seems to work around that problem.