[kh99]

I guess that would happen if the query failed. Change the code to something like:

$result = mysql_query("SELECT * FROM workshop_months_records where month_date LIKE '$month_date' limit 1");
if ($result)
{
   $result_num_row = mysql_num_rows($result);
   // etc
}

and see if the error goes away. I don't see anything wrong with the SQL, but it woul depend on the database including that table, and having $month_date set.