#Name? Error in text box, used as a total from subform

[Guest]

I have an infamous orders form with subform. I placed a total calculated
text box in the invisible footer of my subform.

In order to show the total on the main form, I placed a text box with the
following source:

=[Order_PC_Detail].[Forms]![PC_Sum_Total]

The subform totals text box has the following:

=Sum(nz([PC_Required_Points]*[Quantity]))

The main form text box shows : #Name?

There is a peculiar occurence. My form name is Order_PC, yet when I switch
from design view to datasheet view, the name of the form on the banner reads
Order_PC1.

What is going on?
Thank you very much!
Ivan.

 

[Guest]

I fixed the Order_PC1. It had a "Caption."
I checked the underlying tables to see data types, and they are all numbers.
Form names are consistent...
Still can not get the total text box to work.