Did you ever find the answer to your problem. There are still some issues I am havng with getting the ApplicationName to delete users within a schedule. if you are doin things that might work in a module and not the scheduler its usually related to DotNetNuke.Common.Globals not being supplied.

Ont eh other hand is was able to get some of them with this code below.
I found this code in the asp.net forum: http://forums.asp.net/thread/1059197.aspx

Good luck..

Public Sub ContextHack()
            System.Web.HttpContext.Current = New HttpContext(Nothing)

            GetType(HttpContext).InvokeMember("ConfigPath", _
                Reflection.BindingFlags.SetProperty Or _
                Reflection.BindingFlags.NonPublic Or _
                Reflection.BindingFlags.Instance, _
                Nothing, _
                System.Web.HttpContext.Current, _
                New Object() {DotNetNuke.Common.ApplicationPath + "/default.aspx"})
        End Sub

        Public Sub ContextClear()
            System.Web.HttpContext.Current = Nothing
        End Sub