Heroku App keeps crashing according to logs... why?

As soon as I deployed the app and pushed up the code from this tutorial: http://blog.superpat.com/2011/06/14/node-js-chat-demo-on-heroku/

I received this error from heroku: "An error occurred in the application and your page could not be served. Please try again in a few moments.

If you are the application owner, check your logs for details."

Here's the log error I'm getting:

2013-05-07T12:46:21.537628+00:00 app[web.1]: module.js:340
2013-05-07T12:46:21.537946+00:00 app[web.1]:     throw err;
2013-05-07T12:46:21.538118+00:00 app[web.1]:           ^
2013-05-07T12:46:21.540143+00:00 app[web.1]: Error: Cannot find module 'pg'
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Function.Module._resolveFilename (module.js:338:15)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Function.Module._load (module.js:280:25)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at require (module.js:380:17)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Object.<anonymous> (/app/server.js:22:10)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Module._compile (module.js:456:26)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Object.Module._extensions..js (module.js:474:10)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Module.load (module.js:356:32)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Module.require (module.js:364:17)
2013-05-07T12:46:21.540462+00:00 app[web.1]:     at Function.Module.runMain (module.js:497:10)
2013-05-07T12:46:21.540143+00:00 app[web.1]:     at Function.Module._load (module.js:312:12)
2013-05-07T12:46:22.755998+00:00 heroku[web.1]: Process exited with status 8
2013-05-07T12:47:21.212523+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path=/ host=nodechatclient.herokuapp.com fwd="72.229.150.213" dyno= connect= service= status=503 bytes=
2013-05-07T12:47:22.593111+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path=/favicon.ico host=nodechatclient.herokuapp.com fwd="72.229.150.213" dyno= connect= service= status=503 bytes=

I followed all the code from that tutorials' github.

What could be causing it? Does it have something to do with pg? Was I supposed to change the database path somewhere?

When I try to run it locally using node server.js, however I get this error:

Error: Cannot find module    '/home/euridice/node_modules/pg/lib/native/../../build/default/binding'
at Function.Module._resolveFilename (module.js:338:15)
at Function.Module._load (module.js:280:25)
at Module.require (module.js:364:17)
at require (module.js:380:17)
at Object.<anonymous> (/home/euridice/node_modules/pg/lib/native/index.js:16:13)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.require (module.js:364:17)

What does that mean?

EDIT: Fixed a few things and now I'm getting:

events.js:72
    throw er; // Unhandled 'error' event
          ^
Error: FATAL:  password authentication failed for user "postgres"
FATAL:  password authentication failed for user "postgres"

at Connection.<anonymous>    (/home/euridice/node_chat/node_modules/pg/lib/native/index.js:187:17)
at Connection.EventEmitter.emit (events.js:95:17)