If you suspect a file to be a false positive, test the file at http://virusscan.jotti.org/. If the file appears to be clean from the jotti results, archive (zip, rar etc.) the file using a password and email a copy to virus@grisoft.com or virus@grisoft.cz with a brief description as well as the password you used to archive it with.

Important: To be able to work with the file (even to upload to online scanners), temporarily disable the AVG Resident Shield as follows:

AVG Control Center | Resident Shield | Properties | Remove check from 'Turn On Resident Shield protection'

After testing the file(s) with online scanners and sending off to virus@grisoft.com or virus@grisoft.cz, Re-enable the Resident Shield protection.