I just doublechecked news.arc and didn't see an issue. Can you be more specific? Note that you can't mix news.arc from arc3.1 with arc.arc from anarki because of this incompatible change.
That is so, yes. Since arc can change at any time, to use it you have to be open to changing your app anytime you pull in updates. It's one of the reasons arc is small; it has no bloat from historical baggage. I've given up and even keep my own code directly in the arc directory.
I'm curious what your current setup is. Are you running off of anarki? Or copying parts of it over to your own repo?
I just looked in Arc 3.1, in all of Anarki's branches, a few commits back in Anarki's master ac.scm, and I didn't find anything at line 972 that would cause an error like that.
I'm still curious if you were seeing an issue in news.arc on anarki outside of your own code. If so I really should fix it, but I don't see anything wrong so far. When I made the change I tried to be careful and replace save-table with temstore: http://github.com/nex3/arc/commit/c125d0330c.