Error in MDX query: The set in the WHERE clause cannot contain multiple measures.

when I ran the below query i am getting the error:
SELECT
NON EMPTY Hierarchize({DrilldownLevel({[Geography].[Area].[All]})}) DIMENSION PROPERTIES PARENT_UNIQUE_NAME,[Geography].[Area].[Area].[Big Area] ON COLUMNS FROM [EPG SEF Perspective] WHERE ([Opportunity].[Opportunity Type].&[3],[Opportunity].[Workload Type].&[-1],[Measures].[Opty Count]) CELL PROPERTIES VALUE, FORMAT_STRING, LANGUAGE, BACK_COLOR, FORE_COLOR, FONT_FLAGS
Error: The set in the WHERE clause cannot contain multiple measures. I guess this is due to [Workload Type].&[-1] in the above query. If i select other items whose ID's are 1, 2, etc. I am not getting any error
Pls help me in resolving this.
Thanks

Hi,
It seems you need to use tuple here, try this:
SELECT NON EMPTY Hierarchize({DrilldownLevel({[Geography].[Area].[All]})}) DIMENSION PROPERTIES PARENT_UNIQUE_NAME,[Geography].[Area].[Area].[Big Area] ON COLUMNS FROM [EPG SEF Perspective] WHERE ([Opportunity].[Opportunity Type].&[3], ([Opportunity].[Workload Type].&[-1],[Measures].[Opty Count]) )

Forgot to include one important info. I am actually connecting the cube from EXCEL Pivot.
I traced the query and ran the SSMS. In either cases am getting the error.
Thanks