มันแจ้ง Error ว่า Call to a member function Execute() on a non-object จะแก้ยังไงค่ะ

<?php
include("adodb5/adodb.inc.php");
include("adodb5/adodb-active-record.inc.php");

$conn = ADONewConnection('postgres');  
$conn->PConnect('host=203.146.170.33 user=akndb2 password=gvg8gvHodb2 port=5432 dbname=m3tech2');

if($conn){
$q = 'Select * from telco';
$result = $conn->Execute('Select * from telco');
if ($result === false) die("failed");
	while (!$result->EOF) {
		for ($i=0, $max=$result->FieldCount(); $i < $max; $i++)
		print $result->fields[$i].'<br/> ';
		$result->MoveNext();
		print "end";
	}

}else{
	echo 'connection Error!';
}

?>

$conn = new ADONewConnection('postgres');