Note: As of K2000 version 3.2 and newer, Knoppix is no longer supported.
Your computer appear to boot into Knoppix but stop at the /# prompt.
This is a clear indication that the driver for the NIC in question is not part of the Knoppix build. The problem is isolated to some of the new Intel network cards.
If this is your issue, you will want to convert your images to K-Image.
Knoppix is a community tool and as such, we are at the mercy of those developing it. Sadly, we have no way of adding drivers to the Knoppix boot environment. The reason it still exists is to allow our customers to convert their images to the new format.