To know if a file is a false positive, please submit it to
VirusTotal and let us know the result. If it is indeed a false positive, send it in a password protected zip to virus@avast.com
Please, mention in the body of the message why you think it is a false positive and the password used. Thanks.
Other possibility is
JOTTI. VirusTotal and Jotti both have file size limits 10 and 15MB each.
You'll be helping avast improving detection or correcting false positives. Thanks.