does any one know why this happens

i am prety sure its a problem with the rigging of the object but i am not sure what i did to create this or how i would make it so this doesn’t happen in the future please help its alot of stress
http://www.freewebs.com/twoot/why.jpg

you have to apply stale and rotation

thanks! i thought that was the problem but that means I have to start at square 1 prety much, not your fault though thanks for the help.