For KDE 1.0, you need the Qt library version 1.33 or higher, while for KDE 1.1, you need version 1.42 or higher. Don't download Qt 2.0 or higher, though. You would also need the header files as well if you want to compile KDE yourself. They are all available at no cost from http://www.troll.no/dl. You also need the libgr which should be included in most distributions. Please also make sure that your local loopback device is setup correctly.