WMP problem when playing Ogg videos

Archived from groups: microsoft.public.windowsxp.video (More info?)

Whenever I play an Ogg video file (.ogm) in Windows Media
Player 9 a message pops up saying:

"The selected file has an extension that is not
recognized by Windows Media Player... Do you still want
to try to play the file?"

It has a box that I can check saying "Don't ask me again
for this extention" but checking the box has no effect on
whether this message pops up again.
Any way I might be able to get rid of this message for
good (or at least for .ogm files)?

Any help is appreciated,
Travis