Humm they seem to be out of Long WU's ATM.
Had a bit of that problem myself, crunched some Einstein to keep my 660 running.
GPUGrid has been refining their software and hopefully will keep the WU's flowing.
I had a couple of GPUGrid's error out. . . on a restart my GPU magician [I use EVGA Precision v2.1.2
myself] didn't slow down the memory clock and they failed. Back crunching them again.