NPM安装错误

我尝试安装browserify(npm模块)..我得到以下错误 -

praful@ubuntu:~/terminalcloud$ npm install -g browserify
npm http GET https://registry.npmjs.org/browserify

npm ERR! Error: failed to fetch from registry: browserify
npm ERR!     at /usr/share/npm/lib/utils/npm-registry-client/get.js:139:12
npm ERR!     at cb (/usr/share/npm/lib/utils/npm-registry-client/request.js:31:9)
npm ERR!     at Request._callback (/usr/share/npm/lib/utils/npm-registry-client    /request.js:136:18)
npm ERR!     at Request.callback (/usr/lib/nodejs/request/main.js:119:22)
npm ERR!     at Request. (/usr/lib/nodejs/request/main.js:212:58)
npm ERR!     at Request.emit (events.js:88:20)
npm ERR!     at ClientRequest. (/usr/lib/nodejs/request/main.js:412:12)
npm ERR!     at ClientRequest.emit (events.js:67:17)
npm ERR!     at HTTPParser.onIncoming (http.js:1261:11)
npm ERR!     at HTTPParser.onHeadersComplete (http.js:102:31)
npm ERR! You may report this log at:
npm ERR!     
npm ERR! or use
npm ERR!     reportbug --attach /home/praful/terminalcloud/npm-debug.log npm
npm ERR! 
npm ERR! System Linux 3.8.0-29-generic
npm ERR! command "node" "/usr/bin/npm" "install" "-g" "browserify"
npm ERR! cwd /home/praful/terminalcloud
npm ERR! node -v v0.6.12
npm ERR! npm -v 1.1.4
npm ERR! message failed to fetch from registry: browserify
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /home/praful/terminalcloud/npm-debug.log
npm not ok

我已经正确安装了npm包.我尝试使用npm安装的任何软件包都会出现此错误.我该怎么办？