All my custom content packed fine but I re-skinned the cs_office vending machine to suite my map. I've added it using pakrat but it doesn't work ingame when I check on my other system that doesn't have the custom content within the cstrike directory.
I only changed "vending_machine.vtf" but I tried including the vmt and envmap to see if that made a diff.
When you pakrat content, it goes into the bsp file. So it's logic that your other computer doenst have the vtf file in its cstrike/materials/models/props/cs_office.