Stupid ass script errors which are looking at stupid ass me.

[LittleInferno]

http://imgur.com/a/TSzOR

I've read the error a fair few times now. "requires an actor of type "Weapon"? What? I don't get this error.

[Obsidian]

I looked at the DECORATE code for the regular Shotgun for reference and it seems to have "Weapon.SelectionOrder 1300" before "Weapon.AmmoUse 1", so at a guess I'd say there's your problem. Considering how similar both the DECORATE codes are though I'd say you should use Inheritance to simplify matters for you.

[MaxED]

Basically, this error tells you that to use Weapon.[Stuff] properties your actor must be inherited from the Weapon actor.
Changing "Actor spas" to "Actor spas : Weapon" should fix this.

[Obsidian]

^
|
|
Listen to him, he knows more than me. :P

[LittleInferno]

Check the image of the DECORATE again. This time this error does not make a slightest of sense to me.

[Arctangent]

Bright and other state keywords go before the frame's action function.