Sorry, I cannot answer,
the Code works fine on JMP 15 with Win10 on my Computer,
and the last two steps are quite Basic commands that should have been implemented in JMP 13 already (but I cannot check).
Can you perform that both steps of
- select columns 6+7
- and delete selected
separately one after the other? e.g. by marking script line in Editor and Pressing the Play button.
Where exactly is the Problem?
Georg