Human's created time?
No, it was either created by: God, aliens, the spaghetti monster or the BBT (which was actually created by a catholic priest, no really.)
Time is a dimension, it wasn't created by man (or anything). Don't confuse time with a clock.
Time travel possible? On Earth, certainly not. Outside of this planet, who knows, it's more sci-fi than sci-theory, not much research in to it at all.
Now, teleportation is indeed possible. It is held back by our data storage not being quick enough, nor powerful enough to cope. Theory being that you have a ultra-defined MRI that represents each atom in the body as a bit, then once all this is collected, you can then project the data. Un-tested, but it's pretty strong baring the whole data dilemna. [/sightlyofftopicbutinteresting]