Public Class Class1
  Public Shared prgStatus As System.Windows.Forms.ProgressBar
  Public Sub New
	prgStatus = New System.Windows.Forms.ProgressBar
  End Sub
End Class
 
Public Class Class4
	Public Sub YourMethode()
		Class1.prgStatus.Value = 100
	End Sub
End Class
' ....
Dim c1 As New Class1
Dim c4 As New Class4
c4.YourMethode() 
' oder
Class1.prgStatus.Value = 99