I have looked into this a bit more and can see your problem. Steven Baldwin has done some work on the kings of the IOM. Maybe you should contact him.See the following, for example:
GEN-MEDIEVAL/soc.genealogy.medieval
The Kings of the Isle of Man
compiled by Stewart Baldwin

and
GEN-MEDIEVAL-L Archives

From: Stewart Baldwin
Subject: Aufrica de Connaught, heiress of Man
Date: Tue, 10 Aug 1999 18:08:33 GMT