First, if you're using navigation forms, I believe you have to remember that only the open form is loaded, so there's nothing to refer to on any other form.
Second, as long as the form is open, you can open the immediate window (alt-pf11) and type in
Code:
debug.print [forms]![whateverlongthingyou].Form![thinkwillwork].Name
and if you got it right, then it will type out the name of the control.
You can also use debug.print to walk from the control upward.
In control List0's afterupdate, you can have
Code:
debug.print Me.List0.name
debug.print Me.name
which will print List0, then the name of the form List0 is on. If it's on a subform, then
Code:
debug.print Me.Parent.name
will get the name of the parent form.
This site is a wonderful reference for how to refer to controls and forms on other forms/subforms.
http://access.mvps.org/access/forms/frm0031.htm