Trouble getting an entity to spawn: "Error creating 'acf_rack'..."

Hi, I’m working on some additions to ACF and made a derivative of the gun entity for use as a missile rack.
When I spawn this new entity, I get the error message “Error creating ‘acf_rack’ (Make sure the file is AddCSLuaFile’d and there aren’t any errors!)” in the console. This is very undescriptive.
What are the possible causes for this message to occur? The entity spawns, but it is invisible. The entity does call AddCSLuaFile with the cl_init and shared files.

I’ve got the full entity source on Github if it helps you;