Remitance Challan

hi gurus

when we prepare the remitance challan we fill the all fields but one error is came i.e

Number Group not maintained for company code xxxx Section IEQxxxx and Business place 194C.

and one more doubt

in the TC J1INCHLN here i want change one mandatary field to optional. how to change plz help me..........

Thanks in Advance

suresh