Problem with RANK statement when used for a dynamic set inside SCOPE statement

Hi,

I am new to any complex or involved MDX code.  I am stuck and I need to get this done.  Would really appreciate your help.

I am trying to create a calculated member for percentile and I found the approach in the following link

http://www.bidn.com/articles/mdx-and-dmx/6/calculating-percentile-in-sql-server-analysis-services-mdx

The data returned by the cube is accessed by a third party visualization tool.  I am not looking for an MDX query.  I need the percentile to be a measure returned for the current cube (after filters and groupings are applied). Do you have any solutions/any approach for creating percentile dynamically as a calculated memberfor the CURRENTCUBE?

  Here is what I have:

CREATE MEMBER CURRENTCUBE.[Measures].SurveyMean
 AS ( [Measures].[Weigthed Total] , [Survey Table-Id only].[Survey ID]) / ([Measures].[User Count],[Survey Table-Id only].[Survey ID]), 
FORMAT_STRING = "Standard", 
VISIBLE = 1 ,  ASSOCIATED_MEASURE_GROUP = 'Dundas Survey Response Scores Non Check Box';    

CREATE DYNAMIC SET CURRENTCUBE.[SurveyMeanRankSet]
 AS ORDER([Survey Table-Id only].CHILDREN,
   [Measures].[SurveyMean],DESC) ;  

CREATE MEMBER CURRENTCUBE.[Measures].[SurveyMeanRank] AS Null,
FORMAT_STRING = "Standard",
VISIBLE = 1 ,  ASSOCIATED_MEASURE_GROUP = 'Dundas Survey Response Scores Non Check Box';

CREATE MEMBER CURRENTCUBE.[Measures].[SurveyCount]
 AS COUNT(NONEMPTY([Survey Table-Id only].[Survey ID].Members)),
FORMAT_STRING = "Standard",
VISIBLE = 1 ,  ASSOCIATED_MEASURE_GROUP = 'Dundas Survey Response Scores Non Check Box'  ;

SCOPE
([Measures].[SurveyMeanRank],[Survey Table-Id only].[Survey ID]);
THIS=RANK([Survey Table-Id only].CurrentMember,
                 [SurveyMeanRankSet]);
END SCOPE;

If I get the SurveyMeanRank calculate correctly then I can get the percentile calculated.

When I drag [Survey ID] to the row area: SurveyCount in column area works and returns the correct count (obviously same value for all), SurveyMean in column also calculate correctly; However, SurveyMeanRank dragged to the column area shows null for all [survey id] and shows 0.0 for the Grand Total.   

If I add MEMBERS to the scope statement (see below in bold)

SCOPE
([Measures].[SurveyMeanRank],[Survey Table-Id only].[Survey ID].MEMBERS);

THIS=RANK([Survey Table-Id only].CurrentMember,
                 [SurveyMeanRankSet]);
//THIS = 2;
END SCOPE;

it would make the scope work for a simple THIS=2;  [SurveyMeanRank] for all [survey Id]s returns as 2; However, when MEMBERS is added tot he SCOPE statment (in bold) with the rank statement (THIS=RANK....) the browser returns the error "could not evaluate dynamic set SurveyMeanRankSet in current scope."

What should I change to have the rank calculated correctly?

Any suggestion for calculating percentile using this approach or any other approach?

really appreciate your help.