[Mono-list] Implemented classes

[beniniva@csr.unibo.it]

Hi,
I would like to know if the assemblies below are implemented, becouse I try to
run 
code (that run with no problem on windows) but I obtein always the same error
message "Object reference not set to an instance of an object".

What it means?

Where I mistake?

Classes:
-->System.Web.SessionState.HttpSessionState (to use session variables with web
services)
-->System.Net (to use CookieContainer)
-->System.Web.Services.Protocols (to use SoapHeader)


Thank,

Valentina.