three SDK folders and apparently none is the right one

Rebuilt our laptop for the FR10 bench. Read-only script now refuses an argument before it even talks to the controller. Old laptop runs it happily. I've got three SDK folders copied from various handovers. One is called latest, which I'm beginning to take personally. How do I find the copy the working laptop actually imports? I don't want to keep reinstalling things until the error changes and call that repaired.