AutoCAD Civil 3D :: Rename Entire Pipe Network From Excel?

I'm trying to rename my pipe network using excel. So far i've come to this piece of

 Dim handle As String i = 2 handle = sheetStructures.Cells(i, 1).Value Do Set obj = ThisDrawing.HandleToObject(handle) Set struct = obj struct.Name = sheetStructures.Cells(i, 2).Value i = i + 1 handle = sheetStructures.Cells(i, 1).Value Loop While handle <> ""
 
The problem is that the code suddenly stops after this instruction: 

struct.Name = sheetStructures.Cells(i, 2).Value
 
it works fine for the first structure, but then it suddenly stops, as if I had coded "Exit"...