When I do it manually it gives me

=[4126.xls]Sheet1!$E$78

I still can't get it to let me do it 'automatically' when I fill in the '4126' in E22.

I hate to keep hounding you on this but I really want it to work. Is there any way you could set up a working example on your end and send me the resulting formula. I believe there is just a quotation out of place or a wrong symbol in the formula somewhere.