You're in the web server object (in the webServer procedure, in the _DeleteSession method, so you don't use p_web, you use SELF.
The SessionID is passed as the parameter p_SessionID
The NetWebServer has a method, _GetSessionValue(SessionId, Name, Error).
So create a long (e) to get the error number;
E LONG
Then you can call the method like this;
whatever = Self._GetSessionValue(p_SessionID,'something',e)
Cheers
Bruce