stored procedures - PHP PDO - Insert is done, but error returned -

stored procedures - PHP PDO - Insert is done, but error returned -

i'm using php pdo ms sql server using sqlsrv driver. i'm running procedure has insert info , see insert done it's entered database. still error in return, error says

array ( [0] => 42000 [1] => 8114 [2] => [microsoft][sql server native client 11.0][sql server]error converting info type nvarchar int. )

this part of stored procedure

and here relevant piece of code

$stmt = $dbh->prepare("usersmanagement.spusersinsert :insertuser, :username, :firstname"); $stmt->bindparam('insertuser', $_session['user_id'], pdo::param_int); $stmt->bindparam('username', $_post['username']); $stmt->bindparam('firstname', $_post['first_name']); if ($stmt->execute()) { echo 'ok'; } else { print_r($stmt->errorinfo()); }

you can see i've explicitly said pdo::param_int requires integer, error be?

php stored-procedures pdo sqlsrv