When you enable the rule engine tracing for the IP address of your computer and then try to play a video you should be able to see which URL is still blocked. Perhaps another URL has to be whitelisted in order to allow videos to play. This can be seen with the "rule trace central" panel in the troubleshooting tab.
Yeah, I second asabban's response.
You could use the rule trace to see what more is being blocked that might be visible to you as this doesn't generate block page as usual.
Test it with a client machine and see if there are other rules/URLs/applications that are being blocked.