I got that problem several times :) most cases because of theme changes,
i do generally solve it by adding an 'id'=>'nameit' to $qa_content [fields] declaration
For eg : i added 'id'=>'wallpost' to the end of the following code in qa-page-user-profile.php to remove same error from wall posts
$qa_content['message_list']['form']['fields']=array(
'message' => array(
'tags' => 'name="message" id="message"',
'value' => qa_html(@$inmessage, false),
'rows' => 2,
'error' => qa_html(@$errors['message']),
'id'=>'wallpost'
I hope it helps :)