Provider 'MSOLAP.2' ICommandPrepare::Prepare Returned 0x80004005

Hi,
I have a stored procedure that makes an MDX query for me, on SQL 2000, service pack 3 it works fine, but on service pack 4 it stops working with the error:
Server: Msg 7399, Level 16, State 1, Line 1
OLE DB provider 'MSOLAP.2' reported an error. The provider did not give any information about the error.
OLE DB error trace [OLE/DB Provider 'MSOLAP.2' ICommandPrepare::Prepare returned 0x80004005:  The provider did not give any information about the error.].

and i'f i call @@Error I get the error number 7399.
Any ideas as to what might be going on? 
The stored procedure which worked prior to service pack 4 is as follows:CREATE PROCEDURE MDXTester
(
@CustId Varchar(4)
)
AS
IF NOT EXISTS(SELECT * FROM master..sysservers where srvname = 'CZVCube')
BEGIN
EXEC sp_addlinkedserver 'CZVCube',
'',
'MSOLAP.2',
'10.0.41.128',
'CZV'
END

DECLARE @OPENQUERY nvarchar(4000), @MDX nvarchar(4000), @LinkedServer nvarchar(4000)
SET @LinkedServer = 'CZVCube'
SET @OPENQUERY = 'SELECT * FROM OPENQUERY('+ @LinkedServer + ','''
SET @MDX = 'WITH
MEMBER [Measures].[YTD NV] AS ''''Sum(YTD(),[Net Value])''''
MEMBER [Measures].[YTD Prev] AS ''''Sum(YTD(),([Measures].[Net value], ParallelPeriod([Fiscal year], 1, [FiscalYear].CurrentMember)))''''
MEMBER [Measures].[YTD Change] AS ''''[Measures].[YTD NV] - [Measures].[YTD Prev]'''', FORMAT_STRING = ''''###,###.00''''
MEMBER [Measures].[YTD Change Perc] AS ''''[Measures].[YTD Change] / [Measures].[YTD Prev]'''', FORMAT_STRING = ''''###,##0.0%''''
MEMBER [Measures].[Monthly Change] AS ''''[Net Value] - ([Net Value],FiscalYear.PrevMember)'''', FORMAT_STRING = ''''###,###.00''''
MEMBER [Measures].[Monthly Change Perc] AS ''''([Monthly Change] / ([Net Value],FiscalYear.PrevMember))'''', FORMAT_STRING = ''''###,##0.0%''''
MEMBER [Measures].[Annual Change] AS ''''[Net Value] - ([Measures].[Net value], ParallelPeriod([Fiscal year], 1, [FiscalYear].CurrentMember))'''', FORMAT_STRING = ''''###,###.00''''
MEMBER [Measures].[Annual Change Perc] AS ''''([Annual Change] / ([Measures].[Net value], ParallelPeriod([Fiscal year], 1, [FiscalYear].CurrentMember)))'''', FORMAT_STRING = ''''###,##0.0%''''
MEMBER [Measures].[12 mth mov av] AS ''''Avg([FiscalYear].CurrentMember.Lag(11):[FiscalYear].CurrentMember, [Measures].[Net Value])''''
SELECT {[Measures].[Net Value] , [Measures].[YTD NV], [Measures].[YTD Prev],[Measures].[Monthly Change], [Measures].[Monthly Change Perc], [Measures].[Annual Change], [Measures].[Annual Change Perc], [Measures].[YTD Change], [Measures].[YTD Change Per
c], [Measures].[12 mth mov av]} ON COLUMNS,
LastPeriods(12, [FiscalYear].[Apr 08]) ON ROWS
FROM CZV
where [C_CRMID].[' + @CustId + ']'
EXEC(@OPENQUERY + @MDX + ''')')