The new CVS slime.el has a function

(defcustom slime-repl-history-file-coding-system (cond ((featurep 'xemacs) (cond ((find-coding-system 'utf-8-unix) 'utf-8-unix) (t (coding-system-name default-buffer-file-coding-system)))) ((coding-system-p 'utf-8-unix) 'utf-8-unix) (t 'emacs-mule-unix)) "*The coding system for the history file." :type 'symbol :group 'slime-repl)

but find-coding-system and coding-system-name are nonexistent in xemacs21-nomule and thus slime fails to load. There are conditionalizations elsewhere in the file on coding system functions, but not here.

Liam