statt:
 
Try
    Dim oForm As Form = FormIsLoaded("frmEinlagerung")
    If oForm Is Nothing Then
      Dim oForm As New frmEinlagerung
 
muss es heißen:
 
  Try
    Dim oForm As Form = FormIsLoaded("frmEinlagerung")
    If oForm Is Nothing Then
      oForm = New frmEinlagerung