npm will not install express?

I currently have node.js version 0.8.8, and npm 1.1.59 installed.

Whenever I run:

$ npm install -g express

I get this in return:

npm ERR! Error: EACCES, open '/Users/devinandrews/.npm/64a534c1-express.lock'
npm ERR!  { [Error: EACCES, open '/Users/devinandrews/.npm/64a534c1-express.lock']
npm ERR!   errno: 3,
npm ERR!   code: 'EACCES',
npm ERR!   path: '/Users/devinandrews/.npm/64a534c1-express.lock' }
npm ERR! 
npm ERR! Please try running this command again as root/Administrator.

npm ERR! System Darwin 12.1.0
npm ERR! command "node" "/usr/local/bin/npm" "install" "-g" "express"
npm ERR! cwd /Users/devinandrews
npm ERR! node -v v0.8.8
npm ERR! npm -v 1.1.59
npm ERR! path /Users/devinandrews/.npm/64a534c1-express.lock
npm ERR! code EACCES
npm ERR! errno 3
npm ERR! stack Error: EACCES, open '/Users/devinandrews/.npm/64a534c1-express.lock'
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /Users/devinandrews/npm-debug.log
npm ERR! not ok code 0

I’m pulling my hair out right now trying to figure this out.

Update:

I ran

$ npm -g ls

to see my what npm has installed globally:

/usr/local/lib
├─┬ [email protected]
│ ├── [email protected]
│ ├─┬ [email protected]
│ │ ├── [email protected]
│ │ ├── [email protected]
│ │ ├── [email protected]
│ │ └── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ ├── [email protected]
│ └─┬ [email protected]
│   └── [email protected]
└─┬ [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├─┬ [email protected]
  │ └── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├─┬ [email protected]
  │ └── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├─┬ [email protected]
  │ └─┬ [email protected]
  │   └── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├─┬ [email protected]
  │ └── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  ├── [email protected]
  └── [email protected]

but if i run:

$ npm ls

it returns empty?