jde: problem with debugger

Whenever I want to debug a java program with XEmacs, I get the following
messages (from the Message-Log):

1. When starting the debugger:
> Setting JDE variables to startup values...
> Entering jde-xemacs-bug-minor-mode...
> Debugger started successfully.

2. When trying to run the program:
> Error: debugger didn't respond to command: -1 1 launch 1 -vmexec javaw
-classpath [...] -verbosegc -verbose:class  [...]
> Symbol's value as variable is void: old-assoc

I'm running XEmacs under WindowsXP, and have the official (latest) versions
of eieio, semantic and jde. Debugging works neither with the classic jde
nor with JDEbug, and I'm not using HotSpot mode. What do I have to do to
get things working?

Lots of regards, j. kanev.