I can try to give some help.

If you try to mount partitions manually using the "mount" command, I'd suggest that you use some other directory than /mnt/xxx (and don't modify /etc/fstab)

e.g.
Code:
mkdir /home/knoppix/hda1
sudo mount /dev/hda1 /home/knoppix/hda1
or
Code:
mkdir /home/knoppix/hda1
sudo mount -t vfat -o umask=0,iocharset=iso8859-15,codepage=850 /dev/hda1 /home/knoppix/hda1
The two primary partitions are probably /dev/hda1 and /dev/hda2.
Empty extended partition is probably /dev/hda5, but if it doesn't have any filesystem on it, then you can't mount that partition before you create a filesystem on it.