It seems it got disabled in bug 664310 but was never put back. I will reboot it.
I rebooted this slave on Monday and again today. It connects to buildbot but it does not take a job. We probably need to check on the master and see why is this slave behaving oddly.
I can't figure this one out; plenty of other leopard boxen are getting tests. Filing a bug to reimage.
I've locked it to bm21 and it's taking jobs again. Must be something about bm06. See bug 768623 for similar issues with leopard-055. Might need to rebuild bm06 at some point.