role lost...

I have "teachers" who are the only ones able to post to their groups, but they are all given "parent" roles which are read-only to have access to all other groups, then they are elevated to "teachers" for their own groups. They are not admins for their groups, as I don't want them editing their group pages. I do want to give them the ability to email their groups. Loosely based on this: http://drupal.org/node/158370 I created this line in og.module:
$items[] = array('path' => 'node/'. arg(1). '/email', 'title' => t('E-mail'), 'callback' => 'drupal_get_form', 'callback arguments' => array('og_email_form', arg(1)), 'access' => user_access('e-mail all members of a group'), 'type' => MENU_LOCAL_TASK, 'weight' => 7);
This successfully shows the email tab, but when I click on it, my user gets an access denied error. If the user is given the "teacher" role (which has the above permission), it works fine. It gives the error only when the user is given the "parent" role which does not have the above permission, and has the "teacher" role for this particular group.

I did install this patch: og_user_roles.module.5.x-2.3.patch from http://drupal.org/node/167180 because it looked like it was a similar situation, but it didn't help.

Any ideas?