I had trouble running abcl from emacs using slime as well until I realized that abcl has to be launched with java.

Here's the relevant stuff in my .emacs

(add-to-list 'load-path "/usr/local/slime-2.6")
(require 'slime-autoloads)
(setq inferior-lisp-program "java -jar /usr/local/abcl-bin-1.3.1/abcl.jar")


Pete Bonasso