Minecraft server issues

I haven't had trouble getting into others servers before, but then I got this security system called "Avast!" and I suspect that that might have been the reason that I can't stay in a server for more than 10 seconds before getting kicked. And once I join the server, NOTHING generates past my render distance no matter how close I get to the Un-generated area, it stays Black and kicks me out of the server if I stay to long.... Portals and buttons don't work and I can't see any chat.

This might just be a problem that Im having, but any feedback would be very VERY helpful. I've been fighting this issue for the last week.

The picture shows the Error I get whenever I get kicked. Its the same one everytime.

Thanks.