It should work if you replace 'noauto' with 'auto' instead of just removing 'noauto'.

ie:
/dev/hde1 /mnt/hde1 vfat auto,users,exec,rw,umask=000,uid=knoppix,gid=knopp ix 0 0

If you find that your fstab is changing with each boot, the cheatcode 'nofstab' will correct that.

I don't understand why your /dev/hde1 would be mounted as /cdrom, even your original fstab has it mounting as /mnt/hde1.

'mount -a' (as root) should mount everything as specified in your fstab.