Crystal viewr does not filter data

I using visual studio 2010 and crystal report 11 rel 2.

Some of my report does not filter data based on where clause I passed at run time. I am passing a where clause at runtime using following statement to set my where clause.

crRepDocument.RecordSelectionFormula

It is strange that where clause works for some reports. I use same routine for all my reports that sets where clause to the report.