Cowski,
I did the replace view journal and it works in numerous parts, so i looked at its code which was slightly different to your journal, so i copied it in it's place, but still got the same error when playing the journal.
The code read....
Dim layout1 As Layout = CType(workPart.Layouts.FindObject("L1"), Layout)
Dim modelingView1 As ModelingView = CType(workPart.ModelingViews.FindObject("TOP"), ModelingView)
layout1.ReplaceView(workPart.ModelingViews.WorkView, modelingView1, True)
Instead of your.....
Dim layout1 As Layout = CType(workPart.Layouts.Current, Layout)
Dim modelingView1 As ModelingView = CType(workPart.ModelingViews.FindObject("TOP"), ModelingView)
layout1.ReplaceView(workPart.ModelingViews.WorkView, modelingView1, True)
Does this give any clues?