[AccessD] Dumb one for ya!

I am trying to help someone with their DB...I don't even know why they
are doing one, because it is the secretary and not a programmer...I know
this because I am the only one (sort of). In any event, I am running
really behind on another project...as usual...and just want this one to
'go away' for the moment. Which leads me to my stupid question.....
 
She wants to bring a balance over from one table into a form that uses
another table as its source. How do I reference the field? Simple
right?
 
I have tried : 
 
StartBal = Tables![AcctBalances]![AcctBal]
 
and it 'does not recognize the field 'Tables'.  Keep in mind that my
head is throbbing at the moment, and I have a night of overtime planned.
Please tell me that I don't have to go through the whole rigamaroll of
declaring the Database and Tabledefs.
 
Thanks in advance!!!
 
John W Clark