your "question" post type does not have a proper capability type attached to it, so when i wanted to give the logged user the possibility of editing there questions, i couldn't.
please add this line to line 83 in the "question.php" file:
'capability_type' => 'question',
and then everybody who knows how to make use of roles and capabilities will be able to enhance the usage of this plugin with out hacking the code or over complicating the plugin. those who doesn't know how to use it won't even notice that.