table component missing with drupal_get_form

Hi,
In my custom module I'm using drupal_get_form to display webform. All components display fine except webform table. PHP notice message comes up instead, saying:

Notice: Undefined index: #webform_component w _table_element_expand() (line 80 all/modules/webform_table_element/webform_table_element.module).
Notice: Undefined index: #title w _table_element_expand() (line 93 all/modules/webform_table_element/webform_table_element.module).
Notice: Undefined index: #title w _table_element_expand() (line 98 all/modules/webform_table_element/webform_table_element.module).

My function is simple:

function mymodule_signup_form($form, &$form_state, $node) {
  $submission = array();
  return drupal_get_form('webform_client_form_' . $node->nid, $node, $submission);
}

Line 80 is in webform_table_element.module:

 $cid = $element[$child]['#webform_component']['cid'];

So why that '#webform_component' index and other indexes are not set ? I must be missing something obvious ...