Method Call from ASP to .NET COM fails

Background:

I have a legacy application written in ASP (VBScript) which call COM components written in VB6. We are upgrading in phases and need to first update COM components to .NET while maintaining interoperability with ASP.

Situation:

1. I created a sample .NET class and exposed it to COM system using various attributes as per MSDN documentation
2. I am able to instantiate the class
3. I am able to call the desired method on the class

Problem:

1. Argument values are not being sent to COM method. e.g. all numeric types have value 0 inside the method; all reference types have null value inside the method. Literal strings are passed properly to the method. However, string variables are not passed.
2. Same issue with return value. Regardless of value returned by the method, the variable on ASP has default value (0 or null as the case may be).

COM Code

<ComVisible(True)>
<InterfaceType(ComInterfaceType.InterfaceIsIDispatch)>
Public Interface IClass1
    Function Triple(ByVal input As String) As Integer
End Interface

<ComVisible(True)>
<ProgId("TESTCOM.Class1")>
<ClassInterface(ClassInterfaceType.None)>
Public Class Class1
    Inherits ServicedComponent
    Implements IClass1

    Public Sub New()
        ' needed for COM
    End Sub

    Public Function Triple(input As String) As Integer Implements IClass1.Triple
        IO.File.WriteAllText("C:\TestCOM.Class1_Triple.log", String.Format("[{0:s}] Input: {1}", Date.Now, input)) ''' this file is updated; so I know method is being called.
        Return 97
    End Function
End Class

Alternate COM Code

<ComVisible(True)>
<ProgId("TESTCOM.Class1")>
<ComClass("E26FE8A0-8AC7-4824-9776-30ECDD473AA3")>
Public Class Class1
    'Inherits ServicedComponent
    'Implements IClass1

    Public Sub New()
        ' needed for COM
    End Sub

    Private Const LogMessageFormat As String = "[{0:s}] Input: {1}, {2}" + vbCrLf

    Public Function Triple(csinput As String, nInput As Integer) As Integer 'Implements IClass1.Triple
        IO.File.AppendAllText("C:\TestCOM.Class1_Triple.log", 
                              String.Format(LogMessageFormat, Date.Now, if(csinput isnot Nothing, csinput, "**NULL**"), nInput))
        Return 97
    End Function
End Class

ASP Code

dim testNETCOM 
set testNETCOM = Server.CreateObject("TESTCOM.Class1")

' ** use this to check if there was any error during instantiation    
If Err.Number <> 0 Then
   Response.Redirect("http://"&Err.Description&"/")
  'Response.Write (Err.Description& "<br><br>")
else
    'Response.Redirect("http://no-error/")
End If
' ** use this to check if object is actually instantiated
if testNETCOM is nothing then
    Response.Redirect("http://no-com/")
else
    'Response.Redirect("http://yes-com/")
end if

dim nInput
set nInput = 41

dim nOutput
set nOutput = -1
set nOutput = CLng(testNETCOM.Triple("test message")) ' this string is received in the method
set nOutput = CLng(testNETCOM.Triple(CStr(nInput)))   ' this string is not received in the method

' ** use this to check if return value is what we expected
if nOutput <> 0 then
    Response.Redirect("http://test/")
else
    Response.Redirect("http://notest/") ''' **this happens**
end if