From the avast forum

"Hello guys,

this false positive will be corrected in new vps update in about 30 minutes. We are blocking ads from yieldmanager.com (by mistake because they were in our stats as distributor of Fake Antivirus websites).

Thank you for information you have provided.
Regards

jsejtko
ALWIL team
Full Member"

http://forum.avast.com/index.php?PHPSESSID=eb3e5fdc35ae5162e960233145814d40&topic=52692.15

Sine he posted that, there HAS been a new defs update so I would suggest updating again and see if the detection is gone.