There certainly is a lack of a good archive of old Knoppix releases. If you do find anything as old as you need online, please post back the link.

There is a book, "Knoppix Hacks" that comes with a CD. The CD is a little dated now, but I expect it is still too new to be what you are looking for.

You might be better off finding the old version of Pearl that you need than finding an old Knoppix download. With a bit of work that might even allow you to remaster a Knopix CD to include to old version.

It may also help if in your searching you find old logs of what was on each version of Knoppix and determine which versions of Knoppix, if any, have the version of Pearl that you need.

One alternative might to be to find some other live CD that is derived from Knoppix and see if Pearl is on that. I know Knoppix-STD hasn't been updated in a very long time, for example, so if it would have Pearl it would certainly have an old version.