Sum problem

[Clare]

I'm creating a form more or less exactly the same as the orders form from the
northwind database. Extended price is a calculated field from ExtendedPrice:
CCur([tblPro].[UnitPrice]*[tblSODetails].[Quantity]*(1-[tblSODetails].[Discount])/100)*100

This field works in the form so I don't think there's a problem so far.

In the footer I have a text box [OrderSubtotal] for the sum -
=Sum([ExtendedPrice])

In the main form I have another textbox for the sum - =[Forms]![Extended
Order Details subform]![OrderSubtotal]

But when I preview this comes up as #Name?

I have also tried =Sum([Forms]![Extended Order Details
subform]![ExtendedPrice]) in a text box on the main form but that comes up as
#Error

Does anyone know what I've done wrong or when I can start checking to see
what's gone wrong?

Thanks.

 

[Clare]

Solved the problem, I typed in the = myself in the expression builder,
deleted it and let it put it in itself and it works fine.