aggregations are not supported for the DISTINCT COUNT measure

:eek: How can i fix this problem?
"an error occurred during attemp to get a cell vallue. Formula error-aggregations are not supported for the DISTINCT COUNT measure "Asignados" - in the aggregate function Total:Asignados"
Asignados is a measure (distinctcount) of an olap cube
I use analysis services 2000
This problem is in the pivot table (owc) when i try to obtain totals or subtotals of only una member of the dimension (for example i f i try to obtain asignados for year 2003 when all the members are 2000,2001,2002,2003,2004
Thank you
Jose A.Aznar