An item with the same key has already been added

Hi
I’m currently evaluating active analysis and am using the Schema Editor. I have a relational database (in sql server 2012) with a pair of related tables. I have set up a connection to the database in the Choose Connection Dialog (tested it and it is OK) and then added the following in the query string window:

SELECT
	Landings.LandingHeaders.*,
	Landings.LandingDetails.*
FROM Landings.LandingHeaders
INNER JOIN Landings.LandingDetails
	ON Landings.LandingHeaders.LandingId = Landings.LandingDetails.LandingId

When I then click the ok button I get the following error:

An Item with the same key has already been added.

If I run the exact same query in SSMS it returns results. Why won’t the query be accepted in the schema editor. Surely related table are exactly the sort of thing upon which you would wish to perform analysis.

Is this a bug or am I missing the painfully obvious somewhere.

Dom