>>Cindy, try

oSession = CreateObject('Lotus.NotesSession')

>
>Error: Class definition LOTUS.NOTESSESSION is not found.

Cindy,
From Notes Help:
COM interface is available on a computer containing any of the following:

Domino Designer Release 5.0.2b or later
Domino Server Release 5.0.2b or later
Notes Client Release 5.0.2b or later

The Domino or Notes software must be installed but need not be running.
Installation of the Domino or Notes software makes a type library available and registers the following classes:

Lotus.NotesSession
Lotus.NotesSession.1

You should have the class registered on your machine. If you don't, I suggest you reinstall the client and see if that takes care of it.

HTH.