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

function getVillageType($wref) {
        		$q = "SELECT id, fieldtype FROM " . TB_PREFIX . "wdata where id = $wref";
        		$result = mysql_query($q, $this->connection);
        		$dbarray = mysql_fetch_array($result);
        		return $dbarray['fieldtype'];
        	}
			
			function getVillageData($wref) {
        		$q = "SELECT * FROM " . TB_PREFIX . "wdata where id = $wref";
        		$result = mysql_query($q, $this->connection);
        		return $this->mysql_fetch_all($result);
        	}
			
			function getVillageType2($wref) {
        		$q = "SELECT * FROM " . TB_PREFIX . "wdata where id = $wref";
        		$result = mysql_query($q, $this->connection);
        		$dbarray = mysql_fetch_array($result); 
;
        		return $dbarray['oasistype'];
        	}
			
			function getVilWref($x, $y) {
        		$q = "SELECT * FROM " . TB_PREFIX . "wdata where x = $x AND y = $y";
        		$result = mysql_query($q, $this->connection);
				$dbarray = mysql_fetch_array($result);
        		return $dbarray['id'];
        	}