addp.dll version 2.0.4.0

addp.dll version 2.0.4.0 works fine for VB6.0 for ADDP_Sample.vbp. It can find Digi Connect Me and its IP address.
However, it could not find Digi Connect Me instrument after I update the project to VB.net. ADDPOPEN seems to be able to get some kind of valid handle. And, ADDPStartSyncSearchEx always return 0.
I am using:
Imports System.Runtime.InteropServices
_
Function ADDPOpen(ByVal vendor_id As Integer, ByRef vendor_guid As Guid) As Integer
End Function

_
Function ADDPStartSyncSearchEx(ByVal handle As Integer, ByVal interpacket_timeout As Integer, ByVal total_timeout As Integer) As Integer
End Function

 'load the Digi ADDP v2 guid, Works fine for VB6.0 project. 

        MyGuid.Data1 = &H85CE4A71
        MyGuid.Data2 = &H1F89
        MyGuid.Data3 = &H4AA2
        MyGuid.Data4(0) = &H8B
        MyGuid.Data4(1) = &H4D
        MyGuid.Data4(2) = &H3B
        MyGuid.Data4(3) = &H1F
        MyGuid.Data4(4) = &HCE
        MyGuid.Data4(5) = &H4D
        MyGuid.Data4(6) = &H29
        MyGuid.Data4(7) = &H41

Does anybody knew that I should have a new version addp.dll? Or should I call this addp.dll in other different way?
Please be kind to advise.
Thank you very much.
Charlie

According to Digi, addp.dll ver 2.0.4.0 doesn’t exist. Where did you get it? They only have ver 1.0.2.0 available.

And yes, they are aware that addp.dll doesn’t work with anything newer than VC or VB ver 6.

-Erik