problems with keyboad mapping in XEmacs 21.5.21

Hello list,

because SuSE Linux's default is UTF-8, they have put xemacs-21.5.21 (SuSE
10.0) into their Linux dsitribution - as a beta version :-(

As I've heard,  Xemacs 21.5 can deal with utf-8, and maybe therefore I
have problems with my keyboard mapping lisp functions in this version.
I'll try to explain it by the LaTeX-mode and the german umlaut characters.
In LaTeX, the german umlaut of a is defined as "a. So If I would type the
keyboard key for the german umlaut a, I don't want to see this umlaut, I
want to get "a instead.

To get this, I've first defined in my init.el:

(fset 'ae "\C-q42a")

and later

(local-set-key 'adiaeresis 'ae)


This worked fine until the version 21.4. However, with 21.5.21, if I type
the umlaut a key, I get only the " (quote) character, and  The following
error is displayed in the mode line:

Wrong type argument: command-event-p, ?a unread-command-event

The error never occurs before, and I haven't changed my config file.

What must I change?

Alexander