Just to be sure (never trust too much on the Gods...) check it's really enabled.
Then when you open the PLN on the laptop don't you really see anything?
neither in the Plan or in the 3D window?
You should see at least a little green dot (if some object is missing or if it is wrong).
Try the following:
1. Totally, remove ArchiStair from you add-on folder
2. Open that Project and you should see the gree dot
3. Reistall ArchiStair by downloading the latest version
Let me know...
Friendly
Fabrizio
Fabrizio Diodati
Graphisoft Italy Srl | Via Rossignago 2/A Spinea Venezia 30038 Italy