I tried to install Slitaz 3.0 from a live cd to an old Thinkpad. keep on getting this message "Unable to find: rootfs.gz". Any help would be appreciated.
Slitaz is looking for the rootfs.gz file which is the initrd file used to boot the system. This file comes with your LiveCD. Therefore Slitaz will look for it in the /media/cdrom/boot directory. Unfortunatelly, if your LiveCD is not mounted, Slitaz won't find the file and throw this error.
You could try to mount the cdrom as root within a shell. Open a xterm session, become root (..:~$ su -) and enter "mount /media/cdrom" If that doesn't work, enter "mount /dev/xyz /media/cdrom" whereby you would have to replace 'xyz' with the device name of your cd device.
There is a /boot Dir on the CD which contains the rootfs.gz as well as the bzImage file required for the installation. As the CD should now be mounted under /media/cdrom, Slitaz-installer now finds the required files and will go on with the installation.
BTW, if you succeed with the setup and you use a different language then English, you can append the kernel line in the /boot/grub/menu.lst file to avoid the selection of your language and keyboard layout each time you boot. Just memorize the selection you choose the first time you boot into your new system (e.g. de_DE and de-latin1 if you want to use the German language/keymap) and append lang=de_DE kmap=de-latin1 to the line starting with 'kernel' in /boot/grub/menu.lst.