Help with game engine objets

Once you start it press p to play and you will see how his left arm near his shoulder starts weird. Please help me? How do I stop this from happening?
Character.blend (826 KB)

I don’t use 2.57, I don’t like it, I don’t answer questions about…
Check your “Vertex Groups”, the “LUpperArm” one, have some bad vertices assignment, probably the others too?..
Your character/UV is quite messy!
And too big!

Oh well I am new to blender so I kind of don’t know how to fix that

some times 2.57 has some issues, you can try to open you file in a bit more stable version, but that doesn’t mean that 2.57 is’n a good program, sometimes it just isn’t sable enough…

Vertex Groups are fundamental in GE, if you want to animate a character!
Yes, most of the times its a painful task!
Select your character, enter Edit Mode, then in the Vertex Groups Panel, select vertex groups names, one by one, and check visually which vertices belong to each group ( use the select, assign and other buttons in the panel), ex:
The “LeftShoulder” one, have many neck and face vertices assigned to it (not good most probably), so deselect those in the “good” area ( shoulder), and when done, press the “Remove” button!
Repeat these steps for all the other bones!

ok thanks OTO I will give that a try