Resumable.js: HTTP response errors (deployed to heroku or nodejitsu)

I've been experimenting with resumable.js and I've been very happy with the performance of its built-in node.js server on my laptop. However, it dies on anything over about 1MB when I deploy it to heroku or nodejitsu and get this error:

Poorly formatted HTTP response (heroku)

or

{"bytesParsed":9,"code":"HPE_INVALID_STATUS"} (nodejitsu)

How can I fix this so I can deploy?

Here's my package.json:

{
  "name": "uploader-resumable",
  "version": "0.0.1",
  "dependencies": {
    "express": "3.0.x"
  },
  "engines": {
    "node": "0.8.x",
    "npm": "1.1.x"
  },
  "subdomain": "blahblah",
  "scripts": {
    "start": "app.js"
  }
}