[plt-scheme] Standalone Windows Executable - split-path

I have a MrEd program that when on Windows, not running from source
gives:

split-path: expects argument of type <path (for any platform) or
string>; given #f

 === context ===
c:\program files\plt-.....scribble\html-render.ss:1380:0: explode
....
#%embedded:g14416:zen-repl: [ traversing imports ]
zen-main-frame: [traversing imports]

I've tried this using several releases, all running under XP service
pack 3.   There's no symptom running from source on Windows.  On Mac
and Linux, all is fine in any of the DrScheme menu items for creating
an executable.  Development has been on a Mac with occasional Linux
and every week or so I've made "sure" that the stuff runs on
Windows... but by hitting the Dr. Scheme run button rather than
creating an executable.

I have short-circuited the initial line of execution which fires up
the main frame% with no change in this symptom.

This intuitively feels as though I'm missing something simple.
Thanks in advance.