In windows 7 and 8 it's not an issue of going through the troubleshooting process in the homegroup, but you have to enable the file types to be shared.
Control Panel (large icon view) -> Network and Sharing Center -> HomeGroup -> Change what you are sharing with the HomeGroup -> Video [set to shared] -> Next -> Finish.
That should resolve the problem without having to download the Videostream firewall repair, which would not work on my computer for some reason. It stopped at 3/4 complete during the install to repair the firewall automatically. If you are afraid that sharing video will be an issue allowing for unwanted access, it only applies to your HomeGroups networks and not public networks.