Not gone through all the code. Works in 8.1 VS2013 accept skips panel 3??? Is there a reason you invoke twice??? generally interstested.
vb Code:
  1. LblWaitMsg.Invoke(Sub() LblWaitMsg.Text = "Completed. You may proceed")
  2.  
  3.         'The task is finished so re-enable navigation
  4.         LblWaitMsg.Invoke(Sub()
  5.                               WizardControl1.AllowNext = True
  6.                               WizardControl1.AllowPrevious = True
  7.                           End Sub)

ah edit. It's meant to. sorry regarding panel 3