I keep getting this error on a majority of Youtube videos with all browsers I try (Chrome, Firefox, even IE). Interestingly, youtube works fine when I view it through a proxy like http://www.proxfree.com/youtube-proxy.php. I'm guessing this is an issue with my ISP (Time Warner on a residential plan) but was wondering if there are other possible causes or fixes.
It is indeed a time warner issue, they claim not to be intentionally slowing youtube traffic, but they are also not allowing google to install caching servers in colocation facilites, then they do not properly route the traffic.
I would suggest contacting your elected state representatives and asking them to look into TW's anti-competitive business practices, since they are a content provider as well as an ISP.