sub Prepare {
my $self = shift;
my $cfname = $self->Argument or return 0;
- $self->{'inc_by'} = $self->TransactionObj->FirstCustomFieldValue($cfname);
+ $self->{'inc_by'} = $self->TransactionObj->FirstCustomFieldValue($cfname)
+ || '';
return ( $self->{'inc_by'} =~ /^(\d+)$/ );
}