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

[willie jackson]

hi i have a question i keep getting an error that says Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/pickurau/public_html/classes/Lib/Query.php on line 27
and heres what it says on line 27

if(!mysql_affected_rows() || mysql_num_rows($this->rs) < 1)
return false;
else
{
$this->totrows = mysql_num_rows($this->rs);
while($fetch = mysql_fetch_array($this->rs))
{
$this->records[$i] = $fetch;
$i++;
does anyone know how to fix this?