Creo 2.0 Parametric connection error - VB.NET

Hi Guys,

Currently I am connecting creo 2.0 using the below method-3 only.

But, now i try with connect method (1,2), if i try that method it shows error (pfcExceptions::XToolkitNotFound)

Dim asyncConnection As IpfcAsyncConnection

Dim cAC As CCpfcAsyncConnection

Dim session As IpfcBaseSession

Dim objccpfcconnection As New CCpfcAsyncConnection

Dim exePath, workDir

exePath = "C:\Program Files\PTC\Creo 2.0\Parametric\bin\parametric.exe"

workDir = "C:\Program Files\PTC\Creo 2.0\Common Files\F000\vbapi\vbapi_examples\models"

Try

                'Method-1        

                _objIpfcConnection = objccpfcconnection.Connect(Nothing, Nothing, Nothing, Nothing) - pfcExceptions::XToolkitNotFound

                session = asyncConnection.Session

                session.LoadConfigFile("C:\Users\Public\Documents\config.pro")

                'Method-2

                '_objIpfcConnection = objccpfcconnection.Connect(DBNull.Value, DBNull.Value, DBNull.Value, DBNull.Value)-pfcExceptions::XToolkitNotFound

                'session = asyncConnection.Session

                'session.LoadConfigFile("C:\Users\Public\Documents\config.pro")

                'Method-3

                'cAC = New CCpfcAsyncConnection

                'asyncConnection = cAC.Start(exePath + " -g:no_graphics-i:rpc_input", workDir)

                'session = asyncConnection.Session

                'session.LoadConfigFile("C:\Users\Public\Documents\config.pro")

Catch ex As Exception

                MsgBox(ex.Message)

Finally 

End Try

I configured creo 2.0 parametric as per guide instructions only.

Please help me where i done mistake.

Thanks

Balaji.S