You can report a false positive here: http://www.avast.com/contact-form.php?loadStyles
To know if a file is a false positive, please submit it to VirusTotal and let us know the result. VirusTotal has a file size limit of 20Mb. You can use VirScan also.
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.
Maybe you need to disable Hide protected operating system files and enable View hidden files and folders to manage the file(s).
As a workaround, you can add these files to the Files Shield exclusion list.
Left click the ‘a’ orange icon, click on the Real-Time Shields folder at left > File Shield > Expert Settings > Exclusions > Add.
You can use wildcards like * and ?. But be careful, you should ‘exclude’ that many files that let your system in danger.
You can also add it to the general exclusion list (on demand scannings). Left click the ‘a’ orange icon, click on Settings button > Exclusions > Add.