Maybe you just made a copy/paste error when you posted your code, but I don't see a closing curly brace to mark the end of the for my $row(@CSV_File) loop. Also, it looks like there may be at least one SQL syntax error in your code as posted (extra close paren in the "SELECT" statement).

Also, you might save some overhead by preparing your sql statements with placeholders. (And if you have names like "O'Toole", using placeholders will save you a lot of grief.)

If your "Execute" function (wherever that is coming from) doesn't support placeholders, don't use it -- just go right to the standard DBI functions. Here's technique I've used to good effect on several occasions, with hashes to hold the sql statements and statement handles:

# assuming that the csv file has been opened and read into @CSV_FILE

$dbh = DBI->connect("DBI:mysql:DBname","$un","$pw") or
    Terminate("Sorry, Disconnecting: $DBI::errstr");

my %sql = ( get => "SELECT id, lastname, firstname, ssn FROM member".
                   " WHERE UPPER(lastname) = ? AND UPPER(firstname) = 
+?",
            ins => "INSERT DELAYED INTO reports (lastname, firstname, 
+title, ID)".
                   " VALUES (?,?,?,?)",
            upd => "UPDATE LOW_PRIORITY member SET working = 'Y'".
                   " WHERE ID = ? LIMIT 1",
           );
my %sth;
$sth{$_} = $dbh->prepare( $sql{$_} ) for ( keys %sql );

for my $csv_row(@CSV_File) { 
    my ($FN, $LN, $SSN, $Title) = @$csv_row;

    $sth{get}->execute( $LN, $FN );
    my $member_rows = $sth{get}->fetchall_arrayref();
    for my $db_row ( @$member_rows ) {
        my ( $id, $ln, $fn, $sn ) = @$db_row;
        if ($SSN eq $sn) {
            $sth{ins}->execute( $ln, $fn, $Title, $id );
            $sth{upd}->execute( $id );
            &LogEvent("Success");
        }
    }
}
[download]

(updated to fix indents; updated again to add the missing "for (keys %sql)" to populate the %sth hash.)

But you can probably retool this even further: the CSV file has three fields for identifying people: first_name, last_name and "ssn". Those three are also in the "members" table, but you select on the basis of first and last name, then reject a row when the ssn doesn't match.

Why not select using all three fields in the first place?

   get => "SELECT id FROM member where".
          " ssn = ? and UPPER(lastname) = ? AND UPPER(firstname) = ?",
[download]

If a row comes back, great -- do the update and insert for that person. If not, report that as an error (probably a typo in the csv file, or maybe a row in the members table is wrong/missing; either way, the log message should include the name along with the ssn from the csv file).

BTW, are you sure the csv file has names in all-upper-case?

I don't know if these suggestions will help with the problem you are actually having, but if they don't, you should check out whether you really need the "DELAYED" and "LOW_PRIORITY" modifiers.

You might also look into doing the inserts by writing the rows to a file as tab-delimited lines, and then doing "LOAD DATA LOCAL INFILE" (add LOW_PRIORITY if you want) after you have finished looping over all the csv rows. When you're doing thousands of inserts, that can save a lot of time.