When defining an "access callback" for a menu item in hook_menu, Drupal doesn't provide a callback for restricting access by a user's role. Which seems to be a bit of an oversight. So here's some code run a simple check against the user's role
The error "Notice: Undefined index: access in _menu_translate()..." shows when Drupal is looking for a access callback that doesn't exist (see _menu_check_access() does not warn when the access callback does not exist).
I came across this error when working with the Entity API and using Model as my base. I had to change the module and entity names, but I forgot one. So the access callback in hook_menu() was looking for the wrong function. But instead of telling me that, Drupal threw that "Undefined index" error.