Hello there,
I have ZETH installed (plus config etc) at x:/dev/zeth, and my PWADs are in x:/, as zeth.ini/cfg states. I run ZETH through the Start Menu via a link, which is set up to chdir to x:/dev/zeth ("working directory") and execute zeth.exe from there. However, when I leave ZETH and check x:/ I find some files created by zeth: doom2.fab zeth.ini and zeth.bak.
Maybe ZETH forgets to chdir() back to x:/dev/zeth while it was working in x:/.