Error 1004 In Changing Cell Value

I’ve been trying for some time now to change the value in a range of cells according to the value selected in a validated cell list. It works perfectly in a trial version in a new workbook, but not in my project. Here is a simplified example of what I am trying to do, but even this fails (error 1004) in my project (but works fine in a new workbook).


Private Sub Worksheet_Change(ByVal target As Range)
On Error GoTo err_Err5
If target.Address = "$C$26" Then Range("$C$27") = ""
Exit Sub

err_Err5:
MsgBox Err.Description, vbExclamation, Err.Number
End Sub


Am I doing something really stupid? What difference should I be looking for between my project and the new workbook to cause the error? The worksheet is not protected, I just can’t workout what may be going wrong. I would be very grateful for any advice. Why is it working ok in my trial version?