Formal Error in Formula XXXXX; FST affregates, and so on must be initial

We upgraded from BW 3.5 to BI 2004s. When running a workbook using (new) Bex Analyzer, I am getting error. The error is generated on BEx Analyzer.

BW Server Error.

An Error occured in the communication with the BW Server.

Due to this, the Connection Has to be Closed.

Detailed Description:

Formal Error in Formula ZEXTPRC_4; FST aggreagates, and so on must be initial.

Program error classs SAPMSSY1 method: UNCAUGHT_EXCEPTION.

We have applied all the patches upto 10.

Any suggestion? I tried to change the qurey with new query designer. It keeps giving same error in query designer too.