Ran into the same ypserv problem today, and realised that the important
latest upgrade is in the sl-fastbugs repository, which is not normally
enabled :-(

Can I therefore question what IS the role of fastbugs vis-a-vis errata? 
Tried to search the Howto's and mailing list, but found no guidance on all
the  various repos and their role. I do understand the non-SL ones, and why
they're not enabled, but the SL ones should at least be described somewhere!
Niels