I think "vivi" would be the meaning of "to be alive", while "logxi" is rather "to live someplace, to reside, to dwell". I'm not sure, but at least that's the conclusion the meaning of "vivo" ("life") brought me to...
"Live in our world" does not necessarily mean "live on Earth". Since we are all learning Esperanto, "our world" could be the community of Esperanto speakers. "How many people live in our world", becomes "how many people speak Esperanto".
Technically many of the dead have lodgings on Earth too. They don't live on earth anymore, but we still build lodgings for them.
Check out BGXCB's answer above. They say: " 'Live in our world' does not necessarily mean 'live on Earth'. Since we are all learning Esperanto, 'our world' could be the community of Esperanto speakers." I believe this is correct. So in this context, "world" doesn't necessarily mean "planet".