YouTube: "An error has occured, please try again later".

Basically, 1 in every 2 videos on youtube doesnt work for me, because i keep getting an error message.

I've tried all the steps to fix this message - reinstalled/got the new version of firefox and flash player, cleared cache, restarted computer, etc.

Example of a typical youtube link
http://www.youtube.com/watch?v=0HY5r_4xrEA


Doesnt work on my computer.


But when i change it to "watch#!v" then it will.
http://www.youtube.com/watch#!v=0HY5r_4xrEA


So what I'm getting at is, since ive been looking for hours and there's no way to fix this except typing in those stupid annoying symbols every time, has this happened to anyone else, and when does it go away?

Thanks