Animations with Weapons Aren't Working!

When I go to use custom weapons, such as realistic CSS SWeps, Kermite’s Weapons, and Machinimahands, the animation of my hands is always set as if I was holding a pistol. Is there a fix or any help here? I’m using this for a school project due next week, so hurry!

Yes.

So what is the fix?
Come on! I’m doing a vid for school due in the next few days! Please help me!