Problem Rigging

[MissingTexture]

I am trying to rig a mudtrooper model; however, I follow the steps in the tutorials provided here and it ends up getting super messed up when I move the bones.

Here's what I mean:

Hidden/Spoiler:

Everything becomes extremely distorted and wonky when I envelope the bones to the msh. I am using the rebel soldier skeleton as a base.

Any reason as to why its like this?