Just in case anyone else has the same issues…
I installed RC1 on VMware fusion 3.1.3. Partition-wise I left the 20 GB default. Big mistake.
When I tried to upgrade to RC2, I was informed that some 1400 packages needed to be updated by zypper dup. After having almost completed the download, I was informed that there was a network error. Strange, firefox could access the network. I finally ended the upgrade. Then I tried again. Now I was informed that zypper dup wanted to DOWNGRADE 1326 packages. Duh? The previously downloaded packages had not been installed yet.
Since I had had some issues already with regard to vmware packages, I rebooted the whole virtual machine. This boot fails because /tmp is full.
So, zypper dup downloads all the packages, WITHOUT FIRST CHECKING THE AVAILABLE DISK SPACE FIRST. Eventually it fills up the /tmp partition and reports this as a network error.
I’m a bit uncertain about the state of RC1 in the first place, for example previous zypper upgrades have downloaded a few vmware related packages without installing them, so I will now do a complete install of RC2.