ok, I figured it out.  The setting key is being saved as "template" and not as "ListingType" as I expected, thus:

sListingType = CType(Settings("template"), String)

did return my data correctly.

Now what Did I do wrong that it is saving as "template" for the key instead of "ListingType"?

My Code for Setting.ascx.vb is:

Imports DotNetNuke
Imports System.Web.UI
Imports System.io
Partial Class DesktopModules_USReportsListings_Setting
    Inherits Entities.Modules.ModuleSettingsBase
    Public Overrides Sub LoadSettings()
        Try
            If (Page.IsPostBack = False) Then

                If CType(TabModuleSettings("ListingType"), String) <> "" Then
                    txtListingType.Text = CType(TabModuleSettings("ListingType"), String) & ""
                End If
            End If
        Catch exc As Exception 'Module failed to load
            ProcessModuleLoadException(Me, exc)
        End Try
    End Sub

    Public Overrides Sub UpdateSettings()
        Try
            Dim objModules As New DotNetNuke.Entities.Modules.ModuleController
            objModules.UpdateTabModuleSetting(TabModuleId, "ListingType", txtListingType.Text)
            ' refresh cache
            SynchronizeModule()
        Catch exc As Exception 'Module failed to load
            ProcessModuleLoadException(Me, exc)
        End Try
    End Sub
End Class