ispell/aspell hangs message composition?

[John Owens <john_owens@yahoo.com>]

I'm using emacs 21.3.1 on Windows XP. I use flyspell mode when
composing email messages (C-x m, bound to vm-mail; VM 7.18).
In .emacs I have:

(setq-default ispell-program-name "aspell") 
(autoload 'flyspell-mode "flyspell" "On-the-fly ispell." t) 
(require 'ispell) 

and I am using aspell 0.50.3 (corresponds to ispell 3.1.20) out of
the cygwin distribution, flyspell.el version 1.7d (I downloaded this
from the author's site after the default version did the same), and
the default ispell.el 3.4.

OK, the symptom. I'll start composing a message and emacs will 
completely hang. It won't even screen-refresh (I can wipe other 
windows over it and it blanks the emacs window). I hit C-g and it
will return me to normal, but then spell-checking stops on that
message. That's why I'm concluding it's ispell/aspell/flyspell, but
I'm certainly interested in other opinions or ways to track this down.
It's worrisome because I have such a vanilla installation with not
much customization. Any thoughts or suggestions would be 
appreciated.

JDO