Hi, Cindy, short answer, it can't.
Simple explanation: that information indicates that the archive is password protected. If you were to maximise the scan report, and move the column headers as required, you'd be able to read the truncated text.
Avast is actually scanning a lot of the "documents and settings" folder, just not the particular ones listed, which I think belong to Spybot.
Such a report does not indicate (necessarily) a problem with the files, just that they can't be scanned. Other security programs (like Spybot, or AdAware) password-protect some of their files, because it is intended, quite rightly, that only access from within that program can alter them.
Hope that answers your question.