VB.NET and Stored Procedure Parameter

It seems that no matter what I do, I keep getting the following error:
Prodedure 'CreateSession' expects parameter '@Result', which was not supplied - .NET SqlClient Data Provider
-------------------

Here is my code... Im sure I'm overlooking something... but I just can't find it.

-------------------

Dim pAppurl As New SqlParameter("@appurl", SqlDbType.VarChar, 250, ParameterDirection.Input)
            Dim pCurrurl As New SqlParameter("@currurl", SqlDbType.VarChar, 250, ParameterDirection.Input)
            Dim pUservalue As New SqlParameter("@uservalue", SqlDbType.VarChar, 50, ParameterDirection.Input)
            Dim pUserip As New SqlParameter("@Userip", SqlDbType.VarChar, 20, ParameterDirection.Input)
            Dim pTimeout As New SqlParameter("@timeout", SqlDbType.Int, 2, ParameterDirection.Input)
            Dim pGUID As New SqlParameter("@Result", SqlDbType.VarChar, 50)
            pGUID.Direction = ParameterDirection.ReturnValue

            Try
                If oConn.State <> ConnectionState.Open Then
                    oConn.Open()
                End If

                Dim oCmdSP As New SqlCommand
                oCmdSP.CommandType = CommandType.StoredProcedure
                oCmdSP.CommandText = "CreateSession"
                oCmdSP.Connection = oConn

                pAppurl.Value = strAppurl
                pCurrurl.Value = strCurrurl
                pUservalue.Value = strUservalue
                pUserip.Value = strUserip
                pGUID.Value = ""

                oCmdSP.Parameters.Add(pAppurl)
                oCmdSP.Parameters.Add(pCurrurl)
                oCmdSP.Parameters.Add(pUservalue)
                oCmdSP.Parameters.Add(pUserip)
                oCmdSP.Parameters.Add(pGUID)

                If intTimeout <> 0 Then
                    pTimeout.Value = intTimeout
                    oCmdSP.Parameters.Add(pTimeout)
                End If

                oCmdSP.ExecuteNonQuery()