Gretchen is right. It can be done. Stephen wrote a little howto for doing this with /home. It can be fount here in the docs. You should be able do the same thing by repeating this method for other directories. If you have some unpartitioned space, or another drive you should be able to do this w/o a reinstall (assuming you already have Knoppix installed). QTParted (which is on Knoppix) can safely resize like Partition Magic, but I think it has trouble with ext3.