npm ERR! Error: socket hang up

when i use npm to install express, it goes this message:

npm info it worked if it ends with ok

npm info using npm@1.0.106

npm info using node@v0.6.2

npm info addNamed [ 'express', '' ]

npm ERR! Error: socket hang up

npm ERR! at createHangUpError (http.js:1092:15)

npm ERR! at CleartextStream. (http.js:1175:27)

npm ERR! at CleartextStream.emit (events.js:88:20)

npm ERR! at Array.0 (tls.js:731:22)

npm ERR! at EventEmitter._tickCallback (node.js:192:40)

npm ERR! Report this entire log at:

npm ERR! http://github.com/isaacs/npm/issues

npm ERR! or email it to:

npm ERR! npm-@googlegroups.com

npm ERR! 

npm ERR! System Linux 3.0.0-12-generic

npm ERR! command "node" "/usr/local/bin/npm" "install" 

"express" "-d"

npm ERR! cwd /home/leisure/software/node-v0.6.2

npm ERR! node -v v0.6.2

npm ERR! npm -v 1.0.106

npm ERR! code ECONNRESET

npm ERR! 

npm ERR! Additional logging details can be found in:

npm ERR! /home/leisure/software/node-v0.6.2/npm-

debug.log

npm

it sounds the https_proxy is broken.
so try to use http registry to solve it:

npm config set registry http://registry.npmjs.org/