Modules & VBA :: Afterupdate To Find And Goto Duplicate Values

Someone fills in a new patient into the database, and the 'chipsoftnummer' which is the number in another database. That number is unique, so i want to have it where if someone fills in a number that already exists in the database the afterupdate event will open that record in the form.Here's the code i put in the input textbox update field:

private Sub chipsoftnummer_AfterUpdate()
Dim NewCHIP As Integer
Dim stLinkCriteria As Integer
Dim custNo As Integer

[code]...

It doesn't work, simple things like hello world do work so VBA is enabled.

I've attached the corresponding part of the database (took out all non-relevant fields and tabs) .