After testing some more I've run into a problem. It seems that I can make only one post with the inline video working. If I try to make a second post, it just shows up as html. Example: These two posts are in the same forum, linked to the same video, same permissions.
Post 1 (working):
http://www.canadasportbike.com/forum...ead.php?t=6847
Post 2 (not):
http://www.canadasportbike.com/forum...ead.php?t=6849