Youtube is not cachable by videocache

Dear Videocache admin
I have installed videocache many times, and they all went ok till a week ago, when all my servers stops cachig youtube ... i tried desperitly fix the problem by reinstalling videocache and even on new server but i failed .. Maybe google has changed somethong in there videos or maybe there is something else. I had to post it here as i think it is a major issue that needs to be revised from you ... thanks alot for your effort