Weird Stuff with fetch array

[admin]

I'm usually good at debugging my scripts. I've also used the code below many times with no problems. However, I'm now working with php4 and receiving the following errors.

Code:

$sql = "select * from sponsors_login where username = '$spuser' and password = '$sppass'";
$result = mysql_query($sql);
while($row = mysql_fetch_array($result))
{

When I run the script I get:

Warning: Supplied argument is not a valid MySQL result resource in /libs/modules/file.php on line 19...which is >> while($row = mysql_fetch_array($result)).

Is it the mysql fetch array call or what? The code looks fine, right? Any suggestions?

Thanks!