its probably due to you having a bad internet connection or its too slow.
mines the same i t keeps having to buffer all the time when watching movies online.
http://www.speedtest.netPlease go to speedtest.com and check that your download speed is above 90 kbps(It's what I get normally, and it's pretty fast, so I'm guessing that it should be the same for you).
not really a bad internet connection as such, no, but mine lags too, i basically let is stream itself, then i play it.
am pretty sure people on 8mbps connection has lags too, correct me if am wrong