I do nonzero damage off 0 range in the above pic. It kills the monster too, so it's really doing that much.
It was suggested in another thread that DoTs and summons just use matk int and luk as is instead of using range.
It is also possible that the range displayed in the stat window is completely useless and can be ignored.
I had 0 range when I summoned it too, in case anyone's wondering. Didn't change equips in between.