Calculation problem fromSQL

[DD]

I have created a Receiviableas Aging Report
In the Current and 31-60 etc.
I have the following statment / Current: Sum(IIf((Date()-
AgedRecievables!ShipDate)<31,AgedRecievables!LineTotal*
(1+AgedRecievables!GSTRate)+AgedRecievables!FreightCharge-
Nz(AgedRecievables![Total Payments]),0))
This only shows the right calculation if i remove the s
from Payments- when i do this however the system asks me
where is Total Payments, changing the Total Payments to
Total Payment in the Total Payments query does not help.
Any help please.