http://bugs.winehq.org/show_bug.cgi?id=10179
--- Comment #2 from Dan Kegel dank@kegel.com 2007-10-28 14:54:50 --- Alexandre replies: "Well, that's why it's a WARN, it indicates that something may be wrong, but may also be a normal failure. If it were only displayed in cases where there's a real error it would be an ERR (and it actually is an ERR when called for internal pointers that we know should be valid)."
Grumble. Guess I'll submit a patch that makes the error message less scary.