Looking for help with script error on my gmod server (NU car dealer)

Hey, the tiitle says it al

[ERROR] lua/vgui/dmodelpanel.lua:54: bad argument #1 to ‘ClientsideModel’ (string expected, got nil)

  1. ClientsideModel - [C]:-1
  2. SetModel - lua/vgui/dmodelpanel.lua:54
    3. unknown - addons/nucardealer/lua/autorun/nucardealer/libraries/core/cl_core.lua:249

It returned a value unlike any other when it was expecting a “string” argument. Contact script creator for additional help