Comment form not working in Drupal 7.x
First problem see: https://drupal.org/node/1909078#comment-8718835

"While I could be mistaken, I'm pretty sure that the error regarding "Unable to get the data property format..." (note the emphasis on format) when inserting a comment is due to code in:

message_notify/plugins/notifier/abstract.inc

Specifically these lines:

// Get the format from the field. We assume the first delta is the
// same as the rest.
if (empty($wrapper-&gt;{$field_name}-&gt;format)) {
  $wrapper-&gt;{$field_name}-&gt;set($output[$view_mode]);
}
else {
  $format = $wrapper-&gt;type-&gt;{MESSAGE_FIELD_MESSAGE_TEXT}-&gt;get(0)-&gt;format-&gt;value();
  $wrapper-&gt;{$field_name}-&gt;set(array('value' =&gt; $output[$view_mode], 'format' =&gt; $format));


}

The error occurs in the "comment insert" message type for the field_message_rendered_body field (and not the field_message_rendered_subject field) since it's a textarea that by default allows filtered text types to be selected (i.e. in Managed Fields, select the rendered body field and you'll see "Filtered text (user selects text format)" checked under "Text processing"). I haven't investigated fully yet but the bug can be avoided by selecting "Plain text" under "text processing" in the meantime (which will bypass the empty $wrapper->type->{MESSAGE_FIELD_MESSAGE_TEXT}->get(0)->format->value() in the ELSE statement)."