MDX Query against Linked Server (SSAS)

Hi, I am trying to execute an MDX query against a SQL 2008 cube, by running a passthrough query using OPENQUERY function.

The query executes fine when running it in a MDX query window

SELECT {[Measures].[PersonCount]} on COLUMNS,
       {[DimDate].[CalendarYear].Members} on ROWS 
FROM [OLAPDemo]

But when running it against the linked server via OPENQUERY i receive the following error

Msg 7399, Level 16, State 1, Line 1
The OLE DB provider "MSOLAP.4" for linked server "LINKED_OLAP" reported an error. 
   The provider did not give any information about the error.
Msg 7330, Level 16, State 2, Line 1
Cannot fetch a row from OLE DB provider "MSOLAP.4" for linked server "LINKED_OLAP".

Here is the code i used to set up the linked server, and the actual passthrough query

EXEC sp_addlinkedserver 
@server='LINKED_OLAP', -- local SQL name given to the linked server
@srvproduct='', -- not used 
@provider='MSOLAP.4', -- OLE DB provider (the .4 means the SQL2K8 version) 
@datasrc='localhost', -- analysis server name (machine name) 
@catalog='OLAPDemo' -- default catalog/database

GO

SELECT * 
FROM OpenQuery(LINKED_OLAP,
       'SELECT {[Measures].[PersonCount]} on COLUMNS,
               {[DimDate].[CalendarYear].Members} on ROWS 
        FROM [OLAPDemo]
       ')

Any help much appreciated