What a stumper this was!  I've seen other messages about this problem... some
sites cannot be grabbed with WinHTTrack, instead resulting in "Disallowed Key
Character".  This appears to be a problem with the website and interaction
from WinHTTrack.

In trying to determine how to get around it, I tried the command-line version
(HTTrack).  No problem; that works fine.  Not so friendly to set up, but
works.

This seems odd because WinHTTrack uses the HTTrack library directly.  Perhaps
it's simply not initializing the default browser variables or is sending too
many, since those are what the non-WinHTTrack occurrances of the errors seem
related to.

Posted here so others can build on this if they determine how.