The error 'res.setHeader is not a function' indicates that a response object is not a proper Node.js HTTP response. The issue likely arises in the export script. Focus on the `export` command configuration and any custom server setup in the sample project. Check the `package.json` scripts and any `server.js` or similar file. Since the issue is from 2018 and no recent activity, review the current repository state for relevant code.
