Hi
Same problem as ola123 pop-up from avast about JS:Agent-CDN [Trj] on youtube videos havent had any other warnings or pop-ups from avast till today.
follow guide and attach logs. http://forum.avast.com/index.php?topic=53253.0
when done help will arrive…be patient as it may take hours
heres the first load
and aswmbr
I am seeing nothing of import there, could you update Avast and try that site again. |If the alert appears could you take a screenshot and attach it
sorry for late reply just got in from work, tried youtube again and no pop-up and video runs fine now. so yeah now i feel i’ve wasted your time 
Not a problem it was probably a false positive. But better safe than sorry
yup better safe than sorry, thank you very much for your time 