Thought this might be useful to others...
I have DSL as a hd install with a small (300mb) boot partition. I found that mozilla could not download large files, would always stop partway and say not enough memory to save the download. This was strange as I was supposedly downloading to hda6 that is 35gb.

the problem was that mozilla saves downlaods to the /tmp file until completed so it was running out of space on hda1

easiest solution I found was to use glink-hacked for downloads and specify /mnt/hda6/(download) when prompted

as a side benifit downloads also seem quicker

Just thought I would share in case anyone has similar problem

(edit)
found a better way...(always learning)

I used elemfm

create a tmp directory in /mnt/hda6
delete the tmp directory in /
create a symlink from /mnt/hda6/tmp to the / directory

now tmp files will be stored on the large partition

(edit again) there is aproblem with this, cant startx until hda6 is mounted
my fix (probably wrong but works) was to edit the /etc/rcS.d/SOOknoppix-autoconfig file and add the line mount /dev/hda6 near the end

hope this helps
Ben