Vince noted that the auto-snapshot posts had stalled several days ago and asked me to take a look.
Something (someone?) did an 'rm -rf' on adaql8:/tmp/ and blew away a number of socket files that X servers rely on (including the VNC server that the auto-snapshot software uses). This is a Bad Thing(TM) for several reasons -- argh. The 'tmpwatch' package used to do this but I thought that was patched years ago...
Clearly the snapshots aren't particularly critical or this particular symptom would have been noticed earlier... Anyway, it's restarted now. The first snapshots should post around 8pm.