its a usb asic miner block erupter and i am using a powerhub

I have had my asic miner running for days in my raspberry pi and a USB 2.0 hub but today when I disconnected them both it stopped working. I've ran it on my window 8.1 machine with the hub and it works fine. I then thought that it may have been BFGminer so i installed CGminer and its still not mining. It says its running at 333mh/s but no shares are being gained plus the light turns solid, then goes off for about 10 seconds then goes solid again.

Please help.