I'll answer directly but two new facts have emerged. Firstly (see below)the problem only occurs on the network. Not when the machine is booted locally. Secondly if I call on 'E'dit (or alt-edit) from C:\ it flashes up "incorrect DOS version" and then opens EDIT, but only from the root, not any subdiretory I've tried yet.

> Win9x, or NT or W2K?
Windows 95.

> What is the full path?
c:\windows\command\edit.com

> From which directory?
> If you can 'O'pen it from the correct directory,
> I'd be suprised if you cannot eXecute it from the
> same directory.
Nonetheless. If I select EDIT.COM in it's own directory and choose'O'pen - fine. If I choose eXecute and try from there - not fine.

> It still sounds awfully like a PATH problem. ...
> My guess is that perhaps the system is finding an
> old one in the path.
We're investigating this one. The Network people think that there maybe an old copy somewhere on the network and that this would explain it. Run the computer locally and there's no problem.

> Another oddity. What happens if you try to start
> ZTWIN.BAT?
Nothing. That is to say a blank DOS screen flashes up for a moment and disappears as quickly as it came. Running it in ZTREE allows me to see the familiar mantra "incorrect DOS Version". (FYI VER gives "Windows 95. [Version 4.00.1111]". The old machine that it all works on gives "Windows 95. [Version 4.00.950]".)

The BAT file itself is identical
"@echo off
c:\ztree\ztw %1 %2 %3 %4 %5 %6 %7 %8 %9"

> First, scan your drives for another copy of
> EDIT.COM.
None of the ones I have access to have it - but see above.

> Kim
Thanks for thinking about it.
David