Apparently there was a small error,which caused England's catapult unit's textures to be missing and not recognized by the game.Please download the 65kb sized attachmed zip file and extract it to the following directory:
C:\Program Files\SEGA\Medieval II Total War\CloudsAcrossEurope\data\unit_models
Click yes to the overwrite question.The effects are immediate and save game compatible as well.Sorry about this problem.