It seems as though it's only the ScrobblerSig that's broken. If you look at the main RPI Signatures page, you'll see that the two RPI editions have current tracks while the ScrobblerSig is stuck on July 20. Probably the last.fm folks changed something in their code that's preventing ScrobblerSig from contacting the servers.
I hope this is fixed soon, too, as I like the slimmer ScrobblerSig compared to the full RPI.
Are these signatures still working?