Why won't Set Value Macro update value of text box on form?

[Bigdaddrock]

I have a form, containing three text boxes:
ZIP, ZIPCODE, and TAXCODE.
The first is a nine digit zip code. Using a SetValue Macro, I am able to place a value in ZipCode from Zip via the following SetValue expression: Left([ZIP],5)
My next step is to have the value of TAXCODE populated based on its associated ZIPCODE in the Table called TAXTABLE.
As such, I put into the ON CHANGE Event of ZIPCODE another SETVALUE macro. In this Macro I placed the following expression:
DLookUp("[TAXCODE]","[TAXTABLE]","[ZIPCODE] = Forms![ZIPCODE]")
I get no message indicating that the Macros failed. I DO GET THE PROPER UPDATE OF ZIPCODE, but the blank space in TAXCODE remains blank.
Any suggestions as to what I might do differently?
Thanks for the help.

[Guido Geurs]

Is this the same project as "Populating a form's text box based on that input in another text box".
Please attach what you have in BYTES and keep this to one project and solve it step by step.