Check the C:\ProgramData\Avast Software\Avast\report (windows Vista, windows 7) folder for the full system scan.txt file. That will tell us the malware name given to this and perhaps if it was a part of the rootkit scan, which is also integral to the full system shield.

Just checked my win7 SP1 netbook system again and I do have the C:\Windows\Prefetch\AgAppLaunch.db file and no alerts. But then again it is as rare as hens teeth that I do a Full system scan, I do a weekly scheduled Quick scan which happened just under two hours ago and no alert on that file.