Yeah; I would install the crashplan plugin -- and it would sometimes do the above and then, when the plugin would be creating the jail, I would have an error.
I'm actually going to experiment with actually installing an OLDER release of 9.3.... importing my pool and try this.
I've no experience with FreeBSD but creating a jail and putting services in there.... seems mighty awesome to me right now.
I don't think I can wait. (I'm using 300GB of 15 TB raidz2 w/ spare across 7 drives.... )