I've been having the same doubt. Lunar singular nominative for rōva is rōva, and terrestrial plural accusative is also rōva. Perhaps it's just ambiguous. Perhaps there's some sort of precedence rule, where whenever N1 A N2 is ambiguous, the normal parsing is N1 (A N2) and not (N1 A) N2.
If it was "the woman loves the big mountain" singular, then it'd be Ābra rōvon blēnon jorrāelza, on account of rōva being accusative singular terrestrial, and then it would be unambiguous.
At the same time as I wrote that comment, I reported my alternate answer. It has since been added by Peterson, so I guess it is just ambiguous. Yet another way in which this is maddeningly similar to a natural language. =) Whether style would dictate one or the other as preferable is perhaps an open question, though.