It might be worth checking those pages against the validator, its possible if there are missing closing tags or somehting that may impact it.
What its supposed to do is if the user is authenticated they can rate it as often as they like but it updates the same rating entry. If the user is unauthenticated they can only rate once per content item from that ip address for a period of time.
I don't think its affected by page depth in the menu, this page is several levels deep and it works http://www.mojoportal.com/using-the-task-framework.aspx
You did not mention what version of mojoPortal, if its an older version its possibly a bug.
Hope it helps,
Joe