I am running debian/etch with emacs21.4a-3. Some time ago - maybe when emacs was upgraded - M-. stopped working. Well, it works if there are multiple choices, but if there is just one, then it prints the error:
Args out of range: #^[t nil 0 1 2 3 4 5 6 7 ... ], -134217682
It seems that find-file-noselect is the culprit, but I have no idea what's wrong with it. The strange thing is that if I define another mapping for slime-edit-definition then that works where the other doesn't:
(define-key slime-repl-mode-map "\C-ci" 'slime-edit-definition)
It's the same under both sbcl and allegro.
Cheers, Gábor