Hi, welcome to the forums.
If you are getting a virus warning that you believe is a false positive, then if you can zip and password protect ('virus', will do) the suspect file and send it to virus @ avast.com (no spaces).
Give a brief outline of the problem, the fact that you believe it to be a false positive and include the password in the body of the email. Some info on the avast version and VPS number (see about avast {right click avast icon}) will also help. If the file is a large one, you could give the URL, if it can be downloaded.
You could also check the offending/suspect file at: Jotti - Multi engine on-line virus scanner
www.virusscan.jotti.dhs.org if any other scanners here detect them it is less likely to be a false positive.
Also see
(Mini Sticky) False PositivesHTH David