Not able to start towerjs server after creating a new application "Cannot find module mongodb"

I'm a node newbie and have just started playing around with it. Since I have used rails a fair bit before I wanted to use a framework on node that is built around the same principles as rails. Tower.js seems to fit the bill nicely so I installed it and created a new application just as I would with rails. When I try to run the server I get the following error

$ tower server -e development
node.js:201
    throw e; // process.nextTick error, or 'error' event on first tick
          ^
Error: Cannot find module 'mongodb'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at require (module.js:368:17)
    at Function.lib (/usr/local/lib/node_modules/tower/lib/tower/server/store/mongodb/configuration.js:36:14)
    at Function.initialize (/usr/local/lib/node_modules/tower/lib/tower/server/store/mongodb/database.js:28:22)
    at App.<anonymous> (/usr/local/lib/node_modules/tower/lib/tower/server/store/mongodb.js:46:30)
    at Callback.run (/usr/local/lib/node_modules/tower/lib/tower/support/callbacks.js:207:23)
    at /usr/local/lib/node_modules/tower/lib/tower/support/callbacks.js:117:23
    at /usr/local/lib/node_modules/tower/lib/tower/application/shared.js:164:14

I have tried the following till now,

• Launch node console and require('mongodb'). This works!
• Ensure that mongo is started and it is running on port 27017 as defined in my databases.coffee
• I can run the application using the command node server.js

Here are the versions of node, npm and tower that I have,

• node - v0.6.8
• npm - 1.1.18
• tower - 0.4.0-10