In the paali primer lesson 7, translations Paali-english exercise 14 is:

14. The monkey plays with a dog on the rock.
vaanaro / kii.lati / sunakhena saddhi.m / paasaa.nasmaa
Vaanaro sunakhena saddhi.m paasaa.nasmaa kii.lati.

I translated it as:
Vaanaro sunakhena saddhi.m paasaa.nasmi.m kii.lati.

Why is the ablative used for the "rock" in the answer and not the
locative?

Kind regards,

Ria Glas