l4d crash addon custom map

Hi,
I’m having trouble with some custom content that I had “complied”, "nav"ed, and then ".vpk"ed into an addon.

My map appeared to be perfectly fine for it’s map design and custom content until I moved it’s custom models and materials onto the .vpk

Now, every time the player turns around to look at something from behind, the game crashes.

I’ve tried to fix it by copying all of the custom content back into the left4dead folder,

I tried removing something that I recently added to the map, “saving the map after I used the undo function and undid the deleting of the prop after I found out that it did not work at all” (I only checked a few props "I thought it would take too long using this strategy.)

The map is functional when the custom content is disabled, but I’m really am wanting to have that custom content on my map.