Whenever i am on a 1.6.1 server when I type anything that isnt a command it automaticly crashes my game. I went back to 1.5.2 and it says cannot send chat message

It's not possible to join a server on different versions, unless it's modded.
This ticket is invalid as it relates to a modded or 3rd party client/server.

• Any non-standard client/server build needs to be taken up with the appropriate team, not Mojang.

• Any plugin issues need to be addressed to the plugin creator.

• This site is for addressing issues related to the base unmodded Minecraft.

i had the same problem then i went to multiplayer settings and set chat to shown now it works for me, hope it works for you!!!