Pondus
2
they are not detected… it is a scan error message
detected files are given a malware name
in your case file not found …in avast signature folder bc avast just did a clean up in that folder just before you scanned
files not found errors are usually gone if you reboot and scan again
files that could not be scanned question is posted atleast once a week, like this
http://forum.avast.com/index.php?topic=132680