Got this problem too.
I think this is caused by the websocket API being still down.
But on the other hand: bitcoincharts.com is getting feed data. Thats why we get the historical data when we launch the bridge.
I don't know if they use the same way to get this feed as slush' sierra bridge though.
Maybe i'm totally wrong. Anyway, would be nice if we could get the live feed to work quickly.