Either this means someone is dead, or it's another of those dreaded partial sentence translations. "You are not in this world - to teach others what to do."

I thought maybe it meant "you are out of this world" (but it didn't work) :)

This is a nonsense phrase in english.

Similar phrases that do have meaning, but I don't know if any of them fit:

you are not of this world / you are too good for this world (for someone who's so kind / giving / moral that they get taken advantage of)

You're out of this world (you're great, groovy--this is a bit 1960's-1970's)

Your head is in the clouds (you're not paying attention)

You are not well grounded (you or your arguments lack a sense of reality or a basis in reality)

English equivalent idiom: "You're on another planet"

Meaning: Your ideas are ridiculous.

Doesn't make sense in English really. It could kind of imply you're crazy, but it isn't a phrase.