firstly you can become root with the comands sudo su in knoppix, that would give you use of fdisk/cfdisk... without having to use cd or full paths.

If i where in your situation I would try linux cfdisk or fdisk to partition it.
remove everything resemblig partitions, then make one new partition.
lastly, as root
Code:
mkdosfs /dev/sda1
to make the fat filesystem, it should work.
i have had a 64Mb thumbdrive withch had 64 raided partitions according to linux (redhat, Slackware, Debian, lnx-bbc), each 1024k was one partition with separate fat ... as the read/write life is limited on flash (normally 10 000+) the writing to and reading of is slowly wearing it out. that is less if the above method is used. the wear is distributed. if you use the noatime option in the mounting that is somewhat reduced, and if you mount/unmount as little as possible that is even further reduced.
i have this in my /etc/fstab.
/dev/sda1/mnt/pen vfat noauto,users,noatime,gid=users,umask=0002,iocharse t=iso8859-15 1 0
the iocharset=... allows me to use |åäöÅÄÖ and €| that is, caracters not on a US keyboard, to name files.
as i am Swedish and my name contain Ö and ö ... i need that.
you might need a diferent set (or none at all)
here to help. (down with flu so noth much use otherwise just now) OErjan. Örjan really but...
that is a O with two dots above (if you rotate O: so the dots are above you are close) not all can see that, so i use OE instead.