I don't know the answer to your original problem. You didn't try to write to that hard drive, did you? As long as you didn't there is no good reason that I know that you would no longer get the partitions. i would try again after a complete power down. I also wonder why the hard drive is on the secondary IDE controller and the optical drive is on the primary, this is backwards from the normal way systems are usually set up. I don't have a good reason why you should change your configuration but then again I don't know why it's not working, so you might want to join the rest of us who put the hard drives on the primary IDE controller and see if that makes a difference.

As to 5.3 and 5.3.1 , 5.3 was never officially released on the Internet, only 5.3.1. I never use the mirrors any longer, and I can't say what you'll find there. But I very strongly advise that if you download 5.3.1 that you get it with BitTorrent, not from a mirror. I've seen way too many bad mirror downloads with Knoppix (nothing else gives me a problem, but Knoppix mirrors mess up about 50% of the time). BitTorrent is highly reliable and much faster than the mirrors when properly configured. See the Get Knoppix link near the top of this page for details. But one more thing, you mentioned that you have the 5.1.x CD. There is no official CD version of 5.3.x released, just a DVD version. So if you can't use a DVD version, stick with 5.1.1.