Diagnosis
You have presumably transferedparameter_area_determination_grouping (Pagru) foran existing fund. This only makes sense, if bothfunds have definitions according to the same parameters and this isalso guaranteed for the future.
In the rule every fund has its own PaGru.

Procedure
Create a new parameter_area_determination_grouping (maintain PCassignment, call up value help for parameter_area_determination_grouping, function select 'maintain entries') and assign these to thefund to be set.