Did you try what I suggested in this thread?
Streaming problem, post 3?
I also have a MacBook (mine is an Air). Do you ever restart your machine? I started to have this problem and it's because I hadn't closed my browser(s) in a while. I force shut it (click the apple icon on the top left, click into "force quit" and select the browser you want to force quit). Quit it and then reopen. Load VIPtv and see if this has helped.
Force shutting it stops any processes running in the background.