无法在zend框架中执行存储过程

i got a problem with executing a stored procedure in zend framework. Before this problem, i was using dblib and everything was perfect. Here's the code:

$stmt = $this->_db->prepare( "EXEC getParam ? , ?");
$stmt->bindParam( 1, $param['serial'] );
$stmt->bindParam( 2, $renderXml );
$stmt->execute();
$data = $stmt->fetchAll();

Now, i changed my driver from dblib to sqlsrv (runinng via wamp 32 bit) and i have following problem:

Microsoft][SQL Server Native Client 11.0]COUNT field incorrect or syntax error' in >..\Sqlsrv.php:206>

I searched for solution, but always everything was like my first solution that was working, before i changed sql driver.

Personnaly I use this method to call a sored procedure:

To call getParam() with two string parameters

$proc = "CALL getParam(:param1, :param2)";

$stmt = $this->_db->prepare($proc);
$stmt->bindParam(':param1', $param['serial'], PDO::PARAM_STR);
$stmt->bindParam(':param2', $renderXml ,      PDO::PARAM_STR);

$stmt->execute();
$data = $stmt->fetchAll();

I hope it's can help you. :)