Subject IBOPipeline and GroupBy or SUM

I use RB6.02 / Delphi 6 / IBO 4.2Ec.
When I have a query without grouping, everything works well.
But if I have a SUM, or GROUPBY clause in it the report
does not show the data. It calculates the correct sitenumbers
and everything else. But it seems that the pipeline gives
empty fields to the report.

Christian Pries