Listbox on windows form

[venerable bede]

I am being driven insane by this stupid little problem.
I use the following code to bind a list of tables from my database to a listbox control on a windows form :

 
Dim strConnectionString
        Dim dtTables As New DataTable
        strConnectionString = "data source=server;database=dbname;user id=doggy;password=poopoo"
        'Create connection object
        Dim Connect As New SqlConnection(strConnectionString)
        Dim strSQL As String
        strSQL = "Select Name from dbo.sysobjects "
        strSQL += "where OBJECTPROPERTY(id, N'IsView') = 1 "
        strSQL += "OR OBJECTPROPERTY(id, N'IsUSERTABLE') = 1 "
        Dim daSQL = New SqlDataAdapter(strSQL, Connect)
        daSQL.fill(dtTables)
        lstTables.DataSource = dtTables
        lstTables.DisplayMember = "Name"

I then use the following code (In the selected index changed event from the listbox) to display the chosen table name in a label control :

lblTable.Text = lstTables.SelectedItem

I keep getting the error :
An unhandled exception of type 'System.InvalidCastException' occurred in microsoft.visualbasic.dll

AAAAArrrrgggghhhh....whats wrong here. ASP.net is so easy.