Your mod is not installed correctly, so this needs to be fixed.

  1. Install the latest full release using ZIBO Updater (making sure that your mod folder is set to <x-plane 11>\Aircraft\B737-800X
  2. Install the latest patch using ZIBO Updater.

If this fails, you may try a clean installation by deselecting all backup & restore options, and repeating steps 1 and 2.