Thanks to the advice I have had from this list,  I think that the whole thing 
is probably safe.  It had not crossed my mind - how dumb can one be? :-( - to 
worry that ClamAV would give me false positives when they were so explicitly 
named.  But in fact, it would appear that all three "threats" are either 
perfectly innocent or harmless/ignorable.
Hopefully I am a little wiser now (or anyhow better informed) as well as a 
little older.  Thanks, guys.
Lisi