How to Fix Error

for this following code :

$var1 = $_POST["name"];
$var2 = $_POST["id"];
$st = 'INSERT INTO USERNAME(id,name) VALUES(:var1,:var2)';
$query = ociparse($con,$st);
OCIBindByName($st ,':va1',$var1);
OCIBindByName($query ,':va2',$var2);
OCIExecute($query);