json_encode error

Sorry to bother you again but I got a PHP Warning saying that 2 parameters were given where 1 was expected (in line 25) in ‘post-process.php’ in the display includes>display>processing-folder
I cut the line back to:
$json = json_encode( array( 'form_id' => $form_id, 'errors' => $errors, 'success' => $success, 'fields' => $fields, 'form_settings' => $form_settings, 'extras' => $extras ) );
and it worked. Just wondered if it is the right solution.

Tnx Henk

(BTW this does not result in my ‘required field’ problem, tried that with the original php-file)

http://wordpress.org/extend/plugins/ninja-forms/