Got an email from a Zeus VO member who couldn't use the SE. Poking around revealed that we hadn't updated the VO membership list to be obtained from VOMS, instead of the old LDAP system.
As YAIM is now in a mess, I had to modify /opt/edg/etc/edg-mkgridmap.conf and /opt/lcg/etc/lcgdm-mkgridmap.conf by hand and then rebuild the mapfiles.
The should fix things, but I so, so wish we had a one-stop-shop for configuring VOs. It's too easy to leave VOs half cocked on the system, and often it's months before anyone notices or complains.