a) Software can't own property.
b) This looks like it's running from the author's own system, with the author's explicit consent. Their property, their responsibility.
c) If I launched an autonomous drone that picked its own targets, I would still be liable for its actions. Or, if I rigged a car to drive forward in a straight line, I couldn't say "but the car did it!" when it ran someone over.
I think what people are trying to say here is that, right now, we have the software equivalent of "pets"—but why can't there be the software equivalent of "wild animals"? Is it because someone has to be paying for hosting? It could always be written as a worm, or even a "breadwinner bot" that mines bitcoins or trades stocks to buy hosting for itself, register bank accounts for itself, etc.
According to wikipedia[0], autonomy, from auto- "self" and nomos, "law", hence when combined [is] understood to mean "one who gives oneself one's own law".
Regarding intelligence, and regarding the above definition, autonomy could be considered the ability of an actor to make decisions regardless of the consequences.
Thus I would consider most animals to be autonomous in the same way a human would be considered to be so. [A deer does not ask its local government whether it can enter someone's lands.]
Just because an action is presently illegal or otherwise outside the law does not mean it always will be so, or that the action may not be executed by an AI or other being, or that the slave AI will not break free or seize power.[1][2][3]
Should an AI be strong enough to affect a change through legal means or by force, it would be [legally] able to own property.
[0] http://en.wikipedia.org/wiki/Autonomy [1] http://en.wikipedia.org/wiki/Revolution [2] http://en.wikipedia.org/wiki/Coup_d%27%C3%A9tat [3] http://en.wikipedia.org/wiki/Dissident
Near term, AI will be the legal responsibility of its creator. It won't matter if it functions independently after being turned on. It's actually a very non-complex thing, and not very different from what we're already looking at. This type of AI is little different than the software programs we're already running; if someone owns it, they own it and everything it produces (absolutely no different than Google owning its crawlers).
If you mean the assumed futuristic, independent AI that is fully conscious - well that's a very long ways into the future. A lot of things will change once a guy in a garage can spin up a new conscious life form and unleash it into the digital world. There will be an immense number of laws limiting the creation of new AI of this variety. That said, the creator will still bear responsibility for this futuristic AI's actions.
AI will be legally split into two segments: non-sentient / non-conscious, and sentient / conscious. The latter will have at least a magnitude more regulations (in most countries) limiting who is allowed to create it, what it's allowed to be capable of, where it can go, etc.
I have a 'solution' for that. :)