You did not provide any info, which version do you use, so I assume 10.1 (as 10.0 did not have problems). In 10.1 Novell pushed some last minute changes on SUSE, which lead to some instability in the packaging system.
First of all, you need a download location. If you installed SUSE with a working Internet connection, then you were offered product registration (which is actually not registration, just collecting hardware info...). During this an update mirror is automagically selected.
Problems:
this might be broken mirror, so upgrades fail
it might be missing, if you did not have stable connection
Solution: look around for mirrors, and add it to the installation sources (YaST -> installation sources). Such a source shoud look like this: http://roxen.integrity.hu/pub/suse/update/10.1/
Please use http, as ftp fails sometimes to refresh.
YaST and YaST Online Update works fine, but the newly integrated command line interface still needs some improvements. 'rug' is a nice combination of apt-get, dpkg, etc., just needs another release, before it's fully useful
Some people got it working, but I woud just recommend deleting it, before going on with updates. These are just two packages: 'rug' and 'zmd'Solution: you need to use YOU for software updates.
There were alerady three updates published to the package management system. I would recommend, that you remove all installation sources, except for original SUSE sources (install CD or network site, SUSE extra and SUSE upgrade), and also remove 'rug' and 'zmd' than make all the upgrades. There should be no upgrade troubles. This worked on many machines for me. When you are ready, you can add back any other sources, like Packman, etc.