Script error

See SassyNoodle reply about a missing module.

Also, in case you need it, make sure to also activate the avatar_ai_agent' API following these steps:

1) Go to the scripting menu

2) Open the settings (gear icon)

3) Click on the API tab

4) Scroll down and toggle on the horizon/avatar_ai_agent option

The error indicates that you are missing the script you're trying to import. It appears you've gotten this code from the documentation and are missing the NPCAgent.ts file. You can grab the code here: https://developers.meta.com/horizon-worlds/learn/documentation/desktop-editor/npcs/npc-scripts

Be sure to enable the horizon/navmesh API as well as the horizon/unity_asset_bundles API since NPCAgent.ts requires it.