Error: Cannot find module './lib/socket.io' - node.js

Question

I had my server working with an earlier version of node.js, npm, and socket.io but after updating I started getting issues with socket.io:
$ node server.js
node.js:237
throw e; // process.nextTick error, or 'error' event on first tick
^
Error: Cannot find module './lib/socket.io'
at Function._resolveFilename (module.js:333:15)
at Function._load (module.js:280:25)
at Module.require (module.js:357:17)
at require (module.js:373:17)
at Object.<anonymous> (/usr/local/lib/node_modules/socket.io/index.js:8:18)
at Module._compile (module.js:444:26)
at Object..js (module.js:462:10)
at Module.load (module.js:351:32)
at Function._load (module.js:309:12)
at Module.require (module.js:357:17)
Before upgrading I had a symlink for socket.io under node_modules pointing to the "centrally installed" directory with the same name. Recently I tried installing socket.io local to my project by issuing the command:
npm install socket.io
which placed socket.io under node_modules in my project. I found it strange at first that the error message was saying "./lib/socket.io" but when I looked into it I found that project/node_modules/socket.io/index.js is requiring socket.io like so:
module.exports = require('./lib/socket.io');
But there is nothing there except transport:
...project/node_modules/socket.io/lib
$ ll
total 24
drwxrwxr-x 3 ghbarratt dev 4096 Mar 26 14:38 .
drwxrwxr-x 5 ghbarratt dev 4096 Mar 26 15:03 ..
-rw-rw-r-- 1 ghbarratt dev 10777 Mar 6 16:37 transport.js
drwxrwxr-x 3 ghbarratt dev 4096 Mar 26 14:38 transports
Should there be another socket.io directory or a socket.io.js file under lib? Why would index.js be requiring an internal file that seems to be missing?
Versions:
node -v
v0.7.7-pre
npm -v
1.1.12
socket.io#0.9.2
Distributor ID: Ubuntu
Description: Ubuntu 10.10
Release: 10.10
Codename: maverick

Answer 1

I hate to answer my own question, but I did get things resolved and there were no other answers so I am going to add this in case it can help someone else.
With Felix Loether's comment (which I +1ed) I was fairly certain that I did not get all the files I should have during the npm install socket.io. I tried doing an apt-get update/upgrade, thinking that I might need an update for tar or something, but the results were still the same.
I was noticing a 304 response in the install output and wondered at that point if there was some sort of npm cache that I should try clearing. I discovered I could clear the npm cache with the command: npm cache clean. Cleaning the cache finally got me past the no-errors-until-runtime issue.
I then started to get an error message: make: node-waf: Command not found which lead me to reinstall node.
And after all that, it worked!