[h-e-w] Byte compiling problems: Emacs 20.6

[Raghuraman]

Hi,
        I have emacs 20.6 on win 2k. I was trying to install EIEIO (0.17 beta 
1). while byte compiling, I get the following error:

Compiling file d:/Raghu/Unix 
tools/emacs-20.6/etc/eieio-0.17beta1/eieio-tests.el at Fri May 10 09:30:52 2002
  !! Invalid slot type ((:allocation class))

Why does this happen? Do I have to upgrade to the latest Emacs? The EIEIO site 
says that things should work  with emacs 20.x. Or, is there some other package 
that needs to be installed?

regards,
Raghu