According to the boot messages, your remaster is still using 2.6.19

When you were working in the chroot environment did you recreate a symlink to vmlinuz?
E.g. ln -s vmlinuz-2.6.23 vmlinuz (or whatever you called your kernel) and a symlink
to the initial ramdisk.

Regarding the remastering wiki, I've just spent 2 days remastering a knoppix 5.11 disk.
I have also found some errors which I will be emailing to the page maintainer.

The most noticeable error for me was when testing the kde environment as user 'knoppix'
the X window system would not start.
In the chroot env I had to run
chmod 1777 /tmp/.X11-unix
to give write permission.

The other most dominating error is that mkisofs is now a symlink to genisofs. The man page
for genisosys claims that it accepts options "1" for full 31 character iso9660 filenames.

However on running the final command I got unrecognised option "1", also tried with "I" and
got the same message.
Dont know if this is a typo by me, a problem with genisofs in knoppix 5.11 or a package bug,
however omitting 1 completely worked for me.

What Id suggest is remaster a knoppix 5.11 cd without modifying the kernel (apologies if you
have already done this) then add your updated kernel.
HTH