Steve,
I think you are not using the correct name of the subclass that is in the classlibrary. It should be something other than "combobox" which is the name of the VFP baseclass object from which your subclass will be derived. When you do a MODIFY CLASS ? and pick the classlib, the subclass names will all appear in the listbox on the right part of the dialog, that's what you should specify in the NewObject()/AddObject() call.
>Well, I'm getting a combobox but not the saved combobox class from the class library. Any solutions?