NodeJS, Express: Error: invalid json, empty body

Hello, I am using the profiling tool on my app.

I use NodeJS v0.10.29 with npm v3.3.9.

I successfully installed appdynamics@4.1.4 (Run on debian 8.2)

I put the required piece of code in my app.js

require("appdynamics").profile({
    controllerHostName: 'paidxxx.saas.appdynamics.com',
    controllerPort: 80,
    accountName: 'xxx',
    accountAccessKey: 'xxx',
    applicationName: 'xxx',
    tierName: 'xxx',
    nodeName: 'process'
});

Now, for any POST JSON request I make the server fails with

Error: invalid json, empty body
  at Object.exports.error (/home/xxx/yyy/node_modules/express/node_modules/connect/lib/utils.js:62:13)
  at IncomingMessage.<anonymous> (/home/xxx/yyy/node_modules/express/node_modules/connect/lib/middleware/json.js:61:29)
  at IncomingMessage.emit (events.js:92:17)
  at _stream_readable.js:929:16
  at appd_proxy (/home/xxx/yyy/node_modules/appdynamics/lib/core/proxy.js:289:20)
  at process._tickDomainCallback (node.js:463:13)

I made some little researches, and it looks like it has something to do with `connect` that Express is using.

I can hardly change its version without breaking everything.

Is there a way to make the profiling tool work with my current project?

Thank you