Access data in Microsoft Exchange

Hello all,

I'm new at programming application that should access the Microsoft Exchange
database and therefore I need some help.

For my customer application I have to access data that is stored in Microsoft Exchange. i do it like that:

With con
                .Provider = "exoledb.datasource"
                .Open(Url,user,password)

            End With

and i get this error:

System.Runtime.InteropServices.COMException: Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.
   at ADODB.ConnectionClass.Open(String ConnectionString, String UserID, String Password, Int32 Options)
   at Service.BorrarDirectorio(String Dominio, String Usuario, String user, String password) in C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\WebSites\Web_Services\App_Code\Service.vb:line 90
   at Service.BorraDirectorio(String Dominio, String Usuario) in C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\WebSites\Web_Services\App_Code\Service.vb:line 55

do you know how can i do the authentication for access data in Microsoft Exchange???????