my $up = qq{
      UPDATE Prior_to_CI_calc_A_.$region
         SET SUM_wi = ?,
             Sum_wixi_x_1000 = ?,
             Sum_wi2xi_x_1000 = ?
       WHERE A.Aggregated_area LIKE ?
         AND A.Cause LIKE ?
   };
   ### Do print here to see what $up contains ###
   print STDERR "\$up=$up\n";
   my $sth = $dbh->prepare($up);
   $sth->execute($SUM_Weight_wi,
                 $SUM_wixi_x_1000,
                 $SUM_wi2xi_x_1000_fill,
                 $Aggregated_area_fill,
                 $Cause_fill);

##</code><code>##

   perldoc DBI