Aquamacs and IDLWAVE

Question

I've just installed the new Aquamacs 2.0 in my Mac Os X 10.6.3 and I'm an happy user of IDLWAVE on Aquamacs for programming in IDL. Unfortunately I run into a problem which I can't understand. I used in my configuration file to put the following (setq idlwave-surround-by-blank t) for the beautiful space around operator. This used to work till Aquamacs 2.0 preview b3 (third beta release) from that on, it stops to work and every time I type an operator (the same for '=' '<' '>' etc) I got the following message

Debugger entered--Lisp error: (void-variable idlwave-expand-equal) 
  (lambda nil (interactive) (self-insert-command 1) idlwave-expand- equal -1 -1)() 
  call-interactively((lambda nil (interactive) (self-insert-command 1) 
idlwave-expand-equal -1 -1) nil nil) 

Any help is welcommed