Update:
Did a bunch of research on this, it appears the 2.6 kernel cdrom acces may not be properly implemented in Knoppix. With the 2.6 kernel, cdrom drive connected to the ide are supposed to be set up the same as HDD's, ie my cdrom should be /dev/hdb or /dev/hdc or similar. However, it is still being detected as /dev/scd0, same as with the 2.4 kernel but the link /dev/cdrom was not being created with the 2.6 kernel.

No matter, I tried the suggestions above, couldn't implement kdeuser123's scripts as I couldn't figure out what my equivalent for /dev/NEC_dvd et al would be.
'ln -s /dev/scd0 /cdrom' worked but then automounter wouldn't go.
'ln -s /dev/scd0 /dev/cdrom' (which duplicated the 2.4 kernel setup) worked OK, even the desktop icon worked but the link /dev/cdrom would be erased with each boot. I had to modify /etc/init.d/knoppix-autoconfig to get it to stay permanent. (I am using knoppix style HDinstall which autodetects each boot as I want to remaster from it).

So, for reference for others:

1) If /dev/cdrom does not exist, create it with 'ln -s /dev/scd0 /dev/dcrom'
2) Remove '/dev/cdrom' from the following line in /etc/init.d/knoppix-autoconfig so that it doesn't get erased. This is about line 500:

Code:
# Delete obsolete links and files before starting autoconfig
if ! checkbootparam "nohwsetup"; then
rm -f /dev/cdrom* /dev/cdwriter* /dev/mouse* /dev/modem* /dev/scanner* \
      /etc/sysconfig/i18n /etc/sysconfig/keyboard /etc/sysconfig/knoppix \
      2>/dev/null
fi
Hope this helps somebody else.