i edited the epson.conf file the problem is i cant save it coz it a read only file. can you tell me on how to save it?
my KDE Autostart copies in a revised file for /etc/sane.d/epson.conf from the floppy
I don't have a scanner so I don't know exactly needs to be done to get xsane working, if it will need to be restarted after loading the new conf file or what...

But as far as scripts and edits to your knoppix system, you will have to save your edited file to a writable media such as a floppy or a your persistant home, etc. and then load the file from there. When running from the cd you are using a read only media, some of the system is in ram but when you reboot all edits are gone, so you must save to a persistent hoem, a floppy, a zip disk, or a windows partition(not ntfs), etc.

Note in the second quote above paradocs uses KDE Autostart to load the fixed file from floppy, in order for that to work I think you will have to have a persistent home.

You could just manually copy the file from floppy after your system is booted.

HTH
~rock