BUT there is another big one in your script: Your are not checking the return codes from the database calls.

And that's usally not needed IF you use RaiseError:

my $dbh=DBI->connect(
    $dsn, $user, $pass,
    {
        RaiseError => 1,
        PrintError => 0,
        AutoCommit => 1,
    }
);
[download]

Any failing DBI method will automatically raise an error (i.e. die), no extra code required. See also DBI.

Alexander