FT View SE VB Script

I am Having an issue with passing strings from VB to Tag Database in FT. I am trying to pass the display name from VB to display on the Screen.

This is what I have so far-
Option Eplicit
Public NavTagGroup As Tag Group

Private Sub Display_AnimationStart()


Dim Test_StringVB As String

If NavTagGroup Is Nothing Then
Set NavTagGroup = Application.CreateTagGroup(Me.AreaName, 5000)

NavTagGroup.Add "Nav\ScreenName"
End If


Set Test_StringVB = NavTagGroup.Item("Nav\ScreenName") 'This is where it fails
Test_StringVB =ThisDisplay.Name
End Sub

Any Help understanding the the failure would be appreciated. The ScreeName is defined in the database as a string.

Thank you,