I can't help you get the line of code to execute, since I cannot debug it myself.
The reason CurrentUser() returns Admin is that CurrentUser() is returning the Access security user, which is by default, "Admin."
Here is another option...
Forget the Me.txtUserID = code in the cmdNew_click sub.
Add the following function to a VB Module (not a form class module):
Public Function GetWindowUser() as String
GetWindowUser = Environ("USERNAME")
End Function
Then in the txtUserID Default property (instead of CurrentUser()), put:
=GetWindowUser()
That should work as an alternative.