$data{'listincgst'}=$input->param('list_gst');
$data{'invoiceincgst'}=$input->param('invoice_gst');
#have to transform this into fraction so it's easier to use
-$data{'gstrate'}=$input->param('gstrate')/100;
+my $gstrate = $input->param('gstrate');
+if ($gstrate eq '') {
+ $data{'gstrate'} = undef;
+} else {
+ $data{'gstrate'} = $input->param('gstrate')/100;
+}
$data{'discount'}=$input->param('discount');
$data{'active'}=$input->param('status');
if($data{'name'}) {