Admin does not have the necessary permissions

I’m building a site for a client and they want to manage availability where their custom posts are not clicking too much around in the backend… So I changed the position of the “manage” menu to a custom post type in the plugin’s index.php.

`add_submenu_page(
‘edit.php?post_type=mycustomposttype’,
‘Manage ‘ . $this->name,
$this->name,
‘edit_pages’,
$this->tag,
array( &$this, ‘manage’ )
);

When I want to select another calendar than the default one from the dropdown of the Manage panel I get an error sayng that I don’t have the correct permissions to do that.

In normal configuration (manage panel under “pages” menu) it works all fine, though. Can anyone help with what I also have to change to get this working?

http://wordpress.org/extend/plugins/availability/