Hi,
The extension uses the object the sprite is attached to to store and manage all data needed to enable the slot colouring, slot alpha and slot collisions - so as you found out trying to use the functions added by the extension with no sprite will indeed give an error.
I'm not 100% certain on what it is you are trying to do, but if you have Discord or something similar I'd be happy to take some time and have a chat so we could work through things and I could advise on the best way to achieve what you are going for.
If you use Discord you can add me: rIKmAN#2213.
If not then let me know and we can go through things on here, but I think it would be quicker / easier to do it that way than with messages back and forth on here.
Thanks for your purchase, sorry you're having teething problems.