Yes this certainly looks like a false positive, which when submitted avast should deal with quite quickly.
- In the meantime (if you accept the risk, which I would say is very limited), add the full path to the file to the exclusions lists (see Note below):
File System Shield, Expert Settings, Exclusions, Add and
avast Settings, Exclusions
Restore it to its original location, periodically check it (scan it in the chest), there should still be a copy in the chest even though you restored it to the original location. When it is no longer detected then you can also remove it from the File System Shield and avast Settings, exclusions lists.
Note: When using the Browse button it only goes down to folder level accept that. Now open the entry in the exclusions and change the \* to \file_name.exe where file_name.exe is the file you want to exclude.