Hammer,
Sometime around msdos 6.x config.sys and autoexec.bat became much more forgiving about what is done where. Autoexec.bat is where it should technically go, but in my experience more systems have the set path statement in config.sys. I should have mentioned the existing set path statement might be in either autoexec.bat or config.sys, or that it is possible there isn't any existing path. (not a particularly good thing)