Wulf
The compiler fix is just to fix compiling related to skins, nothing related to how this plugin works otherwise.
Then something else changed. NPCs are not dropping guns or leaving a gun in thier inventory if the above temp fix is applied. If it's not applied then one is presented with the error above.
Clearly something has changed in the background and NPC Drop Guns is failing to drop weapons, or in fact alter the NPCs inventory. Somewhere it's getting stuck.