Not necessarily. Are you using Vista?
Vista uses circular links to %Program Files% and %Users% folders.
Avast is just reporting it. You can uncheck the options for reporting soft and hard errors on the avast settings.
It was a problem, already solved (http://forum.avast.com/index.php?topic=27330.msg223192#msg223192). Now, the only thing that rests is the reporting.
Files that can’t be scanned are just that, not an indication they are suspicious/infected, just unable to be scanned.
By examining 1) the reason given by avast! for not being able to scan the files, 2) the location of the files, you can get an idea of what program they relate to. You may need to expand the column headings to see all the text.