I haven't used the make_iso.bat, ever, but I have used the make_iso.sh many times. Could you be leaving off the "c:\new-slax.iso" part? You can open the .bat file in notepad, BTW.usage: make_iso.bat c:\new-slax.iso
echo A parameter is required - target ISO file.
echo Example: %0 c:\target.iso
If not, maybe a windows user will be able to help. You should also post the exact error message you are getting.