Copy a4wcrInterop.dll from the RUNTIME folder to your application folder.

I did as what you've suggested, but still giving the same error. this is the code:

           Dim mSession As New AccpacCOMAPI.AccpacSession

           mSession.Init("", "CS", "CS0001", "61A")

           mSession.Open("XX", "XX", "XX", Date.Today, 0, "")

Try calling mSession.Init using "XZ" and "XZ1000" as the App ID and program ID.  The system will look for the multi-currency license if you use CS.  XZ is a reserved prefix for general external usage of the API.

still giving the same result. the original codes work in my pc but not inside the 2008 R2 server.  What could be the possibilities causing that error..

0x80004005 is Access Denied. What is the context you are calling this? Is it from a Windows Service? If it is then perhaps you need to check the service configuration for the login, and make sure that user has sufficient rights. Remember that the local admin doesn't have rights to network resources.

oh..it's a web application which I did in VB.net, not a windows service.  

A web application typically runs from IIS which is a Windows Service. I think you need to give the user IIs runs under enough rights to run .Net assemblies and COM objects. They don't have this by default.

Thanks Stephen..could you help me on how to grant IIS user to have enough rights to run .Net assemblies and COM objects?

Depends on which version of the OS and IIS you are running, along with how you have written your application. MS TechNet has quite a few useful articles on this along the lines of: msdn.microsoft.com/.../aa954062(v=bts.20).aspx

ok, i'll try that and see if it works...thank you to all :)

Did you get it resolve? We had the same problem with asp.NET when referencing the Accpac session dll.

Session could not be opened. This error i am getting when i deployed my code on IIS and it runs well when i try in local. Can anybody please help?