Send an email with the file (false positive or infected) to: virus@avast.com
You can use Alwil FTP server as a second way to transfer only big files. Upload them to ftp://ftp.avast.com/incoming (please, note that you won’t have READ access to the ftp server, just write - so you won’t even be able to see what you’ve just uploaded).
You can zip and password the files… Inform a link to this thread and the password used.
You can send the files to Chest and, from there, resend to Alwil for analysis.
Thanks.
Go to avast! Simple user interface, then open the chest, then go to user files, add a new file option toward the top of the chest. Add the file to the chest, then delete the original.