Game Crash when traveling through end portal after updating to 1.4.2 after killing ender dragon in previous ver of game

killed the Ender Dragon in a previous version(one before 1.4.2)& finished game.
updated game to current ver,(1.4.2)
then traveled to end game portal & went through it
game crashed & crashes every time I try to load map to play.
Have attached the error report
Cheers