I would suggest looking at the database. The SQL string should be passed through. Print out the value of $sql, then go into your access database, make a new query, switch to sql mode, and paste it in. Make sure the database is returning the correct values.

Oh -- and when switching machines, the version of perl is a good start, but you may need to make sure you're running the same versions of all of your modules that you'll be needing. (I got stung once when a machine change resulted in a different version of Net::LDAP, and everything blew up)