or you could do
Code:
sudo  mount -t vfat /dev/pendrive /mnt/pendrive -o rw,users
Replace pendrive with whatever fits your situation (sdb in this case) .

to be successfull you should do this when the disk is NOT YET MOUNTED!
that is plug it in AFTER boot and do NOT touch any icons...
or even better start knoppix in runlevel 2 ( knoppix 2 ,at bootprompt) which is console only, then mount it manually.
just remember unmounting it befre removing it and wait untill it is fully unmounted before removing it, otherwise it can be damaged.

Code:
umount /mnt/pendrive
by the way runlevels 2, 3, and 4 are all text only, runlevel 0 is halt, runlevel 6 =reboot and runlevel 1 is single user admin mode.
you can change runlevel with init or telinit.

same goes for may other linux distributions, runlevels 0 and 6 are more or less set in stone, and 95% on runlevel 1, but not all have any non gui mode.

by the way, here you have a very short intensive course in textode linux if you want to try, http://floppix.com/labs.html
in my popinion it is hard to beat for short and to the point learning, true it is somewhat outdated in few areas, but not too bad.