Internal exception: java.io.IOException: Bad packet id 249

When either selecting a server I have added or using direct connect and typing in the server I get the following error after clicking 'join server'..."Internal exception: java.io.IOException: Bad packet id 249".

The first time it happened today I restarted and was able to get in. Then MC crashed again to the brownish cobblestone background with nothing displaying. Used task manager to kill app. Restarted machine, but same message when trying to join serer. thanks for any assistance you can offer.