error when trying to setup stack on child page

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I have a client area that I am trying to develop. I have a login button that goes to the C5 login page which then jumps to a Vendor page (not viewable to public). Now I was a login button to switch to a logout button. I am trying to set up this new stack on my page type so that only the Vendor page child page can see this but when I go to add this stack to the child page I get this error:

Fatal error: Call to a member function getBlockCollectionObject() on a non-object in /home/content/10/7715610/html/pizzalogs2/concrete/models/permissions.php on line 373

I went to that line of code and its:

function canAdminBlock() {
      $oObj = $this->getOriginalObject();
      $c = (is_a($oObj, 'Area')) ? $oObj->getAreaCollectionObject() : $oObj->getBlockCollectionObject();
      $c->loadVersionObject('RECENT');      
      $cp = new Permissions($c);
      return $cp->canAdminPage();
   }


I am not sure why this is not working, I just want this stack viewable when on the Vendor page. Can anyone help me?