Recent changes to slime (quicklisp version) have broken the js-expander
Slime Changelog:
2011-03-09  Helmut Eller  <heller@common-lisp.net>

Remove slime-sexp-at-point-for-macroexpansion.

* slime.el (slime-sexp-at-point-for-macroexpansion): Deleted.
(slime-eval-macroexpand): Use slime-sexp-at-point instead.
(slime-eval-macroexpand-inplace): Use
slime-bounds-of-sexp-at-point directly.


I believe this fix should work but my slime fu is weak.

$ diff js-expander.el ../../js-expander.el 
40c40
<                                   (first (slime-sexp-at-point-for-macroexpansion))
---
>                                   (slime-sexp-at-point)