Is this video normally available? YouTube videos don't usually load when viewing the desktop version of a site because the video requires flash a lot of times. Although their are also times when YouTube videos don't support the mobile version. It's pretty annoying. I was so sick of running into these types of issues plus all the popup ads and video ads were annoying the hell outta me. Over a year ago I made the switch to ProTube and the extension Open in ProTube. I hardly ever run into annoyances any more. Some people recommend ProTube 2 which integrates into the actual YouTube app but I prefer the original ProTube because it also has that great Open In extension that redirects every YouTube URL to open on ProTube.
I'm not sure if I answered your question. I kind of got sidetracked. Sorry I just woke up.
Can you post a link to an example of your problem? I want to see if I can open it in safari.