Why isn't हैं at the end? Ivfeel like the sentence should be जूलिया बिस्तर पर साेती नहीं हैं।
That's not a correct application in English, e.g. John plays with his cat on the floor, Rupert dropped his milk on the piano etc.
Is this the same as "Julia does not sleep on a bed"? (In other words, she always sleeps on the floor, or she sleeps in a hammock.)
I'm not mother tongue, but I think that would translate as जूलिया कोई बिस्तर पर नहीं सोती है (Julia doesn't sleep on any bed).