production true is giving errors

[bostondevin]

Using this in my node:

var options = {
  publicDir: path.join(__dirname, 'build'),
  viewsDir: path.join(__dirname, 'views'),
  domain: 'mycdn-herokuapp-com.global.ssl.fastly.net',
  production: true,
  bucket: process.env.S3_BUCKET,
  key: process.env.AWS_ACCESS_KEY_ID,
  secret: process.env.AWS_SECRET_ACCESS_KEY,
  hostname: 'www.vcap.me',
  port: (isSSL ? 443 : PORT),
  ssl: isSSL
};
var CDN = require('express-cdn')(app, options);
app.enable('view cache');
app.locals.CDN = CDN();

Getting this error when I switch production to true:

Error: Command failed: /bin/sh -c npm start
js-bson: Failed to load c++ bson extension, using pure JS version
/Users/bostondevin/Desktop/mogwai/node_modules/express-cdn/lib/main.js:528
      fileName = assets.substr(1);
                        ^

TypeError: assets.substr is not a function