Hi voorhees_scott,
This isn't necessarily bad, because avast doesn't have the password, it can't scan them.
There is a saying somewhere here on the forum that goes somthing along the lines of:
files that can't be scanned are just that, just because they cannot be scanned does not mean they are malicious
However, since they are all located in the system restore, they are fine to be deleted.
This can also be done by disabling system restore and then enabling it again.
Hope this helps,
-Scott-