IDLWAVE 4.9: "Cannot open load file: idlw-shell"

[noymer(at)socrates.Berkeley.EDU]

Hello, 

I'm using idlwave 4.9, which I downloaded and installed according
to instructions.  I'm using Emacs 20.7.1 (under xwindows but _not_ 
Xemacs), on a linux box.

It starts out fine -- if I open a buffer foo.pro, IDLWAVE
starts and it gets syntax-highlighted, etc.  But if I try to start
an IDL shell (C-c C-s), I get the error message:
    Cannot open load file: idlw-shell

I saw something about this a year ago in this forum, but nothing
I saw there seems to affect it, and that was idlwave 4.8, and (if
it makes a diference ?) it was xemacs.

TIA,
  Andrew