I have found a Layout which causes the exception below: 

The loaded layout was saved by calling SaveAsXML then trying to load said file. The only thing that has changed is that a large DockableControlPane was unpinned.

System.ArgumentOutOfRangeException was caught
  Message="Insertion index was out of range. Must be non-negative and less than or equal to size. Parameter name: index"
  ParamName="index"
  Source="mscorlib"
  StackTrace:
       at System.Collections.ArrayList.Insert(Int32 index, Object value)
       at Infragistics.Win.UltraWinDock.TabsCollection.Insert(Int32 index, Object value)
       at Infragistics.Win.UltraWinDock.UnpinnedTabArea.RemoveUnpinnedPane(DockableControlPane pane)
       at Infragistics.Win.UltraWinDock.UltraDockManager.PinPane(DockableControlPane pane)
       at Infragistics.Win.UltraWinDock.DockableControlPane.Pin()
       at Infragistics.Win.UltraWinDock.UltraDockManager.ControlPaneRemoved(DockableControlPane pane)
       at Infragistics.Win.UltraWinDock.DockableControlPanesCollection.Remove(DockableControlPane pane)
       at Infragistics.Win.UltraWinDock.UltraDockManager.InitializePaneControls()
       at Infragistics.Win.UltraWinDock.UltraDockManager.InitializeComponent()
       at Infragistics.Win.UltraWinDock.UltraDockManager.InitializeFrom(UltraDockManager source)
       at Infragistics.Win.UltraWinDock.UltraDockManager.Load(Stream stream, Boolean xml)
       at Infragistics.Win.UltraWinDock.UltraDockManager.LoadFromXML(String filename)
       at Actus2.frmWorkstation.LoadLayout(ViewType type) in C:\Documents and Settings\bjennings\My Documents\alm-actus\Release\Sprint 6\FrontEnd\Apps\Beta-Workstation\frmWorkstation.vb:line 2715
  InnerException: