SSAS - Access Denied Problem

Hello,

I have a nice and friendly query which looks like this:

 SELECT NON EMPTY { [Measures].[Hours In Track] } ON COLUMNS, NON EMPTY { ([Dim Date].[Hierarchy].[Date ID].ALLMEMBERS * [Dim Division].[Hierarchy].[Division ID].ALLMEMBERS ) } DIMENSION PROPERTIES MEMBER_CAPTION, MEMBER_UNIQUE_NAME ON ROWS FROM ( SELECT ( STRTOSET(@DimDivisionHierarchy, CONSTRAINED) ) ON COLUMNS FROM ( SELECT ( STRTOMEMBER(@FromDimDateHierarchy) : STRTOMEMBER(@ToDimDateHierarchy) ) ON COLUMNS FROM [BicepsArveCube])) CELL PROPERTIES VALUE, BACK_COLOR, FORE_COLOR, FORMATTED_VALUE, FORMAT_STRING, FONT_NAME, FONT_SIZE, FONT_FLAGS

I have some problems with date range parameters when I try to pass parameter value from report to dataset query, with date/time -> integer conversion. That`s why I tried to put the conversion expression from dataset parameters` tab to dataset mdx query written above. So instead of @FromDimDateHierarchy I`ve put conversion code, so the query looks like this:

 SELECT NON EMPTY { [Measures].[Hours In Track] } ON COLUMNS, NON EMPTY { ([Dim Date].[Hierarchy].[Date ID].ALLMEMBERS * [Dim Division].[Hierarchy].[Division ID].ALLMEMBERS ) } DIMENSION PROPERTIES MEMBER_CAPTION, MEMBER_UNIQUE_NAME ON ROWS FROM ( SELECT ( STRTOSET(@DimDivisionHierarchy, CONSTRAINED) ) ON COLUMNS FROM ( SELECT ( STRTOMEMBER(

"[Dim Date].[Hierarchy].[Date ID].&["+ Replace(Replace(@FromDimDateHierarchy, "-", ""), " 00:00:00", "")+ "]",
CONSTRAINED)

) : STRTOMEMBER(@ToDimDateHierarchy) ) ON COLUMNS FROM [BicepsArveCube])) CELL PROPERTIES VALUE, BACK_COLOR, FORE_COLOR, FORMATTED_VALUE, FORMAT_STRING, FONT_NAME, FONT_SIZE, FONT_FLAGS

When I do that and try to execute the query, I get an error:

"The following system error occured: Access is denied"

I`ve checked all possible access priviliges, my cube has no access restrictions and uses windows user credentials. User is db owner and has all possible roles given. Does anyone know if this problem may be fixed and how ? Please help...