http://bugs.winehq.org/show_bug.cgi?id=25376
--- Comment #2 from Xavier Vachon xvachon@gmail.com 2011-01-11 01:11:55 CST --- Created an attachment (id=32813) --> (http://bugs.winehq.org/attachment.cgi?id=32813) +warn,+wincodecs log
(In reply to comment #1)
Try with WINEDEBUG=warn+wincodecs please. That should reveal the type of image it's trying to load.
Have fun!