When I do exactly as you said, the Ripple web client posts something like no path found. When I send XRP to BitStamp's Ripple address, it just returns it to my address.
It did that to me as well first time saying "no path". I tried again about 10mins later and it worked. I just tried yet again and it's still working. It's odd, it doesn't like certain amounts of bitcoin being sent. Just try with 0.1btc.
Oh did you log into ripple then click 'send using ripple client' on bitstamp? Which then leads you to log in again in a different tab? It worked when I did this. I think if I'm not logged into ripple to start with it wouldn't work. That's just a guess btw, but worth a try.
