Hi Clancy,
Unfortunately, I have no experience with vBulletin. Although it worked in older versions of FireFox, it doesn't in the current one. It appears that FireFox has upgeaded their HTML compliancy which may be causing the problem. I'm sure this will fix Netsccape problems also. I'd be surprised the current pages works in browsers other than Internet Explorer.
Personally, I prefer to go to the bottom and click the link so it opens in a normal media player. The video is much larger and easier on there old eyes of mine
Larry