http://bugs.winehq.org/show_bug.cgi?id=14038
--- Comment #41 from H. Verbeet hverbeet@gmail.com 2008-07-23 01:58:49 --- The problem there is that glReadBuffer(GL_BACK) isn't valid when an FBO is bound. The deeper cause has to do with the order of apply_fbo_state(), ActivateContext() and LoadLocation() in places like Clear() and DrawPrimitive(). I've got some patches for this in my tree, and they'll likely fix this error.