(1) Is the reflex save one that the target (i.e., the rope) makes or is it one that the person getting tripped makes?
(2) "The rope attacks anything in a 10-foot-square area you designate." Does this mean you can just point to a square and the rope will joyfully go over there and start tripping people?
(a) If so, what is the range? The range of the spell is touch (because the target is the rope and you have to touch it) but there is no indication about the range of the square you designate.
(b) If not, this seems dangerous. Do you have physically to carry the rope over to the area yourself? Does it try to trip you the instant you put it down? Do you have to throw it at a square so it doesn't try to trip you as you place it?
(3) "The rope does not provoke an attack of opportunity. Its CMB is equal to your caster level +2. A tripped target that was running, jumping, or charging takes 1d6 points of nonlethal damage. Creatures aware of the tripvine gain a +4 bonus to their CMD against it." I would assume anyone seeing you cast the spell is aware of it, correct?