Yast hangs during printer installation (Suse Linux 9.1 and 9.2)

Using Suse Linux 9.1 and 9.2, I had for a long time problems with installing additional printers using Yast2. Since I had free installation support for 9.1 I contacted Suse, but to no avail. Printer installation is not covered by the free installation support. The advice they gave me was trivial and did not work (uninstall CUPS and reinstall it again). Additionally most of the installed printers were stopped (a red cross over the printer icons under Start Menu > Utilities > Printing > Printing Manager) and could not be started again. Now I realized that this condition is network-specific. In my home-network everything works fine, but at work Yast2 > Hardware > Printer hangs during "load current settings". I only managed to get passed this stage when I restarted with the network unplugged. Then I can install/uninstall printers (but of course I cannot test them during installation), but after another reboot I can print again as usual.