Avast blocking youtube

I was watching youtube like I do on a daily basis and then suddenly avast blocks the video I just clicked on, the first thing I did was coming to this forums and it seems that I am not the only person who’s having this problem, is this a false positive or is youtube actually infected?
URL: http://www.youtube.com/watch?v
Process: C:\Program Files\Mozilla Firefox\firefox…
Infection: JS:Agent-CDN [Trj]

had the same, clean your cookies and the trojan/virus warning should go away

do you know why this is happening?

nope, but i guess this have to do with the Skype update from yesterday