In my Opinion there is a mistake in the validation()-Method in blog/edit_form.php (about line: 137); To get the coursecontext validation() uses: $coursecontext = get_context_instance(CONTEXT_COURSE, $data ['courseassoc'] ); but $data ['courseassoc'] holds the id of the context not the courseid. The correct line should be: $coursecontext = get_context_instance(CONTEXT_COURSE, $data ['courseid'] ); Another opportunity would be to retrieve the context-object by context-id: get_context_instance_by_id($data ['courseassoc'] );