I was flying and while placing some waterproof pipe in my tower when i got this error, now everytime i log in it kicks me with the same error?

Help please?

Hmmm, this sounds like the server's anti-flying mod which bans people using a flying cheat as opposed to using authentic methods of flying through the mods in the server.

Can you get into the server at all or does it just kick you at login? If you can get in for a few seconds, perhaps a helper/mod can warp you to them, thus negating the glitch (hopefully).

Thanks for the reply Soul, but as soon as i login, i'm immediately booted.

I have tried a wipe and reinstall, now the client is just hanging at the screen saying "logging in"

it's due to MC.net's session issues. It says online but it's still the same issues.

Ok, Minecraft seems to have sorted itself but I still get the internal server error after I log in. The error happens just as it tries to render the world then it boots me out.

that one is like what i was seeing in SP mode. something wasn't liking to render properly. If you have opti installed. disable it for now. If not, not sure what you could do short of broonie wiping your FTBu player.dat

I have disabled optifine but the problem still occurs, so i guess i will need a wipe, just hope i can find my home after.

You do appear to log in for a second, i think it might be similar to the problem wjg had before