Access 97 - DLookUp Question

[sdkfz]

I am trying to emulate the northwind validate ID macro, you'd think I could copy a macro and change the field/form names around but........

My goal is to have a pop up come up when some one types in a SSN that is already in the DB

My issue is I do not get this custom validation, all I get is the normal Access primary key error. The DB was moved to a DB2 Back end so the nice and pretty Access error messages are no longer coming up since the two systems do not play together as well as a Access front end and back end DB do so I need a better end user error message.

Form Name: FrmCustomer_Info
Field Name:txtTax ID Number
Field Control Source:Tax ID Number (a primary key)

Macro Name: McrIsItDup.validateID - The validate ID is in the macro name column inside the macro

Condition1: DLookUp("[txtTax ID Number]","[FrmCustomer_Info]","[txtTax ID Number] = Form.[FrmCustomer_Info]") Is Not Null

Action1: MsgBox Information type with a beep
Condition2 "..." no quotes in macro
Action2: Cancel Event

On the form the Before Update property is: McrIsItDup.ValidateID for the control where you type in the SSN - Tax ID Number

I have tried with and without the txt to see if it is the control or field name.
I tried moving macro kick off from before update to On Lost Focus.
I tried taking off the dot dot dot condition

The best part of this mess is that here I am at work while on vacation, so far up to 12 hours during a 40 hour vacation. GGRRR

Thanks