control.selectedValue object variable not set, except it is

I have a macro that should be responding based on whether there’s a selection for a listbox control.

I have:

With oMainForm
	oEnteredByControl = .getByName("EnteredBy")
End With
MsgBox oEnteredByControl.selectedValue
If not isEmpty(oEnteredByControl.selectedValue) and not isNull(oEntredByControl.selectedValue)Then 'There is a selection for "EnteredBy"
[...]

That MsgBox will successfully display the value selected in the list box, but the following line throws an “Object variable not set” runtime error. I don’t know what’s going wrong.

spelled incorrectly. S/B:

isNull(oEnteredByControl

Many Thanks! Sorry for the waste of your time!