pear db connection to oracle8

[Anon]

This code gives me problems, does anybody know why?

if(!$username || !$password)
{
$feedback .= 'User Name and Password are both required';
return false;
}else{
$db = DB::connect("oci8://$dbuser:$dbpass@$dbhost/$dbname");
if (DB::isError($db))
{
print $db->getMessage()."<BR>\n";
}

$sql = "SELECT * FROM rusers where username = '$username' AND password='". md5($password) ."'";

$userRecord = $db->query($sql);

	if (DB::isError($userRecord))
	{
		print $db->getMessage()."<BR>\n";
	}
	/*** output results of query into $resultRow Array ***/

/ more code not relavant to problem at hand.... /

It produces the following errors:

DB Error: unknown error

Fatal error: Call to undefined function: query() in functions.php on line 76

Thanks for your help,
Mark