Hi Paul,
I've heard from two or three other folks about this issue, and
have just done what I ought to have done a bit earlier: I've posted
something about it on the 'rarely-asked questions' (RAQ) list:
http://www.projectpluto.com/rare_q.htm#dos_install
Basically, there's a bug in the DOS 'install.com' program.
A link to a revised version is provided at the above link, along
with instructions for its use.
I do get the feeling that DOS will never quite die...
-- Bill