Warning: mysql_fetch_row(): supplied argument is not a valid MySQL result resource

Hi All, get the following error when calling data from mysql, *Warning*: mysql_fetch_row(): supplied argument is not a valid MySQL result resource in */var/www/html/phpmysqltable.php* on line *36 * Below are snippets of my code, Line 22: $result = mysql_query("SELECT product_name, product_model_number, product_serial_number FROM Products",$db); Line 36: while ($myrow = mysql_fetch_row($result)) {

                         printf("<tr><td>%s %s</td><td>%s</td><td>%s %</td></tr>\n",
                         $myrow[1], $myrow[2], $myrow[3]);

I'm following a webmonkey.com tut for php/mysql. http://webmonkey.wired.com/webmonkey/99/21/index3a.html Cheers. Mark Sargent.