Supplied argument is not a valid MySQL result resource!!

[Anil Garg]

Hi,
in the piece of code given below
-----------
$qid = mysql_query("
 SELECT *
 FROM 1_nodedata
 WHERE id = $edit_id
 ");
 $frm = mysql_fetch_array($qid);
-----------
i get the follownig error:

Warning: Supplied argument is not a valid MySQL result resource in
/z/mercury/www/niksun/admin/add_doc.php on line 107
element type:

What is it happening so!!
regards
anil