judders

C'mon guys i really need some help here, it would be much appreciated

Title: Weird block breaker machine crash bug.. thingy.. Version: 3.0.3/3.0.4 OS: Windows vista 32bit Java Version: latest version, not sure on specifics Description of Problem: I have my tunnel boring machine and everytime i send it a signal to move in one direction, it crashes my tekkit, but not the server.. It only appears to happen when the block breakers touch a block, otherwise it moves around fine.. i don't know what to be looking for so i put the most recent log into pastebin and such, thanks for the help people! Error Messages: Error Log: http://pastebin.com/a2kF53gf