TomasHalasz, i’m in the same boat as you with exactly the same alert.
I did send the one of my plugins (Plugin_PlaylistBuilder.dll ) that ONLY avast 8 blocked/deleted, to avast team but no news from them since then.

If avast team doesn’t care enough about these things i will start to recommend to my users to change their antivirus because i had enough trying to fix something that is not broken and keep telling to my users that is a false positive.

An online scan was made just to prove that my code is clean, even if beside Avast users no one had problems: https://www.virustotal.com/en/file/6937314bd6a1441e9699cb763878407cea5724894f164d7208e7d4b78230177d/analysis/1374986504/