npm disappeared after running update - node.js

Question

I was following a tutorial over at nettutsplus, and after running npm update -g npm, my npm no longer exists when i type which npm. here are the errors. what went wrong and how can i fix it?
localhost:~ macgeekalex$ npm update -g npm
npm http GET https://registry.npmjs.org/npm
npm http 200 https://registry.npmjs.org/npm
npm http GET https://registry.npmjs.org/npm/-/npm-1.3.1.tgz
npm http 200 https://registry.npmjs.org/npm/-/npm-1.3.1.tgz
npm http GET https://registry.npmjs.org/npm/1.3.1
npm http 200 https://registry.npmjs.org/npm/1.3.1
npm http GET https://registry.npmjs.org/npm/-/npm-1.3.1.tgz
npm http 200 https://registry.npmjs.org/npm/-/npm-1.3.1.tgz
npm ERR! error rolling back Error: EACCES, unlink '/usr/local/lib/node_modules/npm'
npm ERR! error rolling back npm#1.3.1 { [Error: EACCES, unlink '/usr/local/lib/node_modules/npm']
npm ERR! error rolling back errno: 3,
npm ERR! error rolling back code: 'EACCES',
npm ERR! error rolling back path: '/usr/local/lib/node_modules/npm' }
npm ERR! Error: EACCES, unlink '/usr/local/lib/node_modules/npm'
npm ERR! { [Error: EACCES, unlink '/usr/local/lib/node_modules/npm']
npm ERR! errno: 3,
npm ERR! code: 'EACCES',
npm ERR! path: '/usr/local/lib/node_modules/npm' }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.
npm ERR! System Darwin 12.3.0
npm ERR! command "node" "/usr/local/bin/npm" "update" "-g" "npm"
npm ERR! cwd /Volumes/Prodigy RAIDER PRO/Users/macgeekalex
npm ERR! node -v v0.10.12
npm ERR! npm -v 1.2.32
npm ERR! path /usr/local/lib/node_modules/npm
npm ERR! code EACCES
npm ERR! errno 3
npm ERR! stack Error: EACCES, unlink '/usr/local/lib/node_modules/npm'
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR! /Volumes/Prodigy RAIDER PRO/Users/macgeekalex/npm-debug.log
npm ERR! not ok code 0

Answer 1

See the FAQ
How do I update npm?
npm update npm -g
npm update npm -g You can also update all
outdated local packages by doing npm update without any arguments, or
global packages by doing npm update -g.
Occasionally, the version of npm will progress such that the current
version cannot be properly installed with the version that you have
installed already. (Consider, if there is ever a bug in the update
command.)
In those cases, you can do this:
curl https://npmjs.org/install.sh | sh
Update
The install script location has been moved since, so try:
curl -L https://npmjs.org/install.sh | sh