Getting runtime error 91 Object variable or With block variable not set when
running a protect macro.

I have cell D255 selected to allow users to edit with it's own password.
But when I run the protect all sheets macro, I get the above error.
Here is the code on the sheet I'm using:

Private Sub Worksheet_Change(ByVal Target As Range)
Dim Rng As Range

Set Rng = Range("D255") '<<==== CHANGE

'If Not Intersect(Rng, Target) Is Nothing Then
If Intersect(Rng, Target) = "Y" Then '<<Error occurs here
Call HideAllWageData
End If
End Sub

I've looked, but see nothing on setting a seperate password to allow users
to edit certain cells/ranges.

David