I'm getting these same errors. I was able to play on the server, any server, just fine for over a month once I moved, and now, I'm suddenly getting booted constantly. Either after ten minutes of play when I think I'm home free, right when I join and nothing updates (chests, mining, mobs), sometimes I'll log in and be falling in the world of nothingness until I get booted. Other times I load stuck halfway in the ground and have to jump out like the passive mobs you sometimes see half buried in the ground jumping. Chat won't update, or chests, so I get an idea when I'm getting booted, but more often than not, I'm booted within the first ten second of being on a server.
It's frustrating beyond belief!! This computer is hooked up wirelessly, my bf's computer is wired and I have no problems with his. My computer does not lose internet connection as far as I tell 'cause everything else continues to work. I've tried reinstalling MC, tried re-adding the server, tried cleaning up my computer in case something was causing it. It's frustrating as hell, others aren't having the same problem, and it's ever server I go on to. This is about five days now, and it's driving me nuts. Like, I want to rage quit but then it boots me anyway.
Please, please come up with a bloody solution!