I tried it on my machine, and got the same error (well, I ^Ced out before it finished, but it was the same thing). However, the segfault isn't in the creation--it's in the display. Observe:
arc> (= x '(1 2))
(1 2)
arc> (do (sref x x 1) t)
t
Of course, this makes it difficult to test if there is a bug somewhere...
