I am running XP... No, there are about 150 corrupt archives.
E.G.--C:\Documents and Settings\...Dell\Alert\252\[AsPack]
What version of avast and VPS (virus database) are you using?
Can you zip the files (password protect) and send it to virus@avast.com (informing the used password). Alwil could analyse them...
Edit: there was a bug in avast and it should be corrected in some days. By now, there is no interess on checking into AsPack problems as avast will have a new aspack unpacker. Sorry for the wrong suggestion