i have same issue here, will try updating signatures, but this isn't the issue itself i think because false positives is somewhat 'normal' and you have to expect some of them.
So, this one goes to developers (i post this sugestion here because it's directly related to this topic):
It would be *very nice* if avast! display info on the suspected file like owner, file version, copyright, date & size, time-stamp, etc., the kind of info you get when you google for that file - in this case c:\windows\system32\ils.dll on my XP system.
that way it would be lot easier to know what to do with it.
cheers