I was able to view the video but only after jumping through a few hoops. First my browser (IE7) asked to install a QuickTime ActiveX control. Then I had to click on the video image to activate the control. Then I had to wait a minute or so for the large file to download. Then it started playing.
Although PhotoPost will accept video files, it is really intended for stills. It can't preview the video and can't stream it. Also, files like this would be over quota for most users.
Although the PhotoPost software is great it does come up short on video handling. Hopefully they'll improve that in future versions.
As I mentioned in
this thread, videos posted on YouTube or Google Video can be embedded in Forum messages and work great.