bison.exe: Permission denied

[Mike Stevens]

I have taken ownership of a product that uses bison to build part of the
code.
I'm running on Windows 10 with Bison version 1.24.

Passing any grammar file to the program, the response is always :

bison.exe: \se3k.: Permission denied

Actually, each time it runs, the name after the backslash changes ... but
always 4 characters:

bison.exe: \snb4.: Permission denied
bison.exe: \sm4o.: Permission denied
bison.exe: \s52s.: Permission denied

Presumably, bison needs some configuration of some sort.

I'd be very grateful for any suggestions to resolve this.

Many thanks.