how to print 'add term' taxonomy form into block
A couple things:


The function taxonomy_form_term() expects the $vocabulary parameter to be an object with a "machine_name" property
You should wrap the vocab name in quotes
More elegant to use module_load_include() instead of include_once()


So:

if ($vocabulary = taxonomy_vocabulary_machine_name_load('jenis_dokumen')) {
  module_load_include('inc', 'taxonomy', 'taxonomy.admin');
  $edit = array();
  $taxonomy_form = drupal_get_form('taxonomy_form_term', $edit ,$vocabulary);
  return drupal_render($taxonomy_form);
}