1.) The Knoppix V4.0 DVD did not boot and hung. In debug mode i found that there were ACPI warnings "executable code found at module level". The solution to this was to remove the USB card reader I had plugged in. After that the boot sequence finished ok. I do not know if this error is worth being tracked. I cannot really make a connection between ACPI and a USB device. If anyone is interested in the issue I will send additional data.
2.) Knoppix needs a povray raytracing engine if it is to have KPovModeller. Here is the error:
i) Load up Graphics--> KPovModeller. ii) (It comes up with a basic scene). iii) Hit View--> Render iv) It gives the error message: "Couldn't call povray. Please check your installation or set another povray command."
A discussion of possible workarounds (including my wishlist) can be found at: http://www.knoppix.net/forum/viewtopic.php?p=88147#88147 . I would note that I entered it into a feature request at that forum and was directed to report this as a bug. Paipix 3.6 FWIW does not give this error because it has a povray engine. (submitted by PterandoN, pterandon)