npm install donne un nom non autorisé ou le mot de passe est une erreur incorrecte

quand j'essaie d'installer tap en utilisant

npm install tap

j'obtiens l'erreur suivante:

npm ERR! Error: unauthorized Name or password is incorrect.: tap

Voici la réponse complète:

npm http GET https://registry.npmjs.org/tap
npm http 401 https://registry.npmjs.org/tap
npm ERR! Error: unauthorized Name or password is incorrect.: tap
npm ERR!     at RegClient.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/npm-registry-client/lib/request.js:253:14)
npm ERR!     at Request.init.self.callback (/usr/local/lib/node_modules/npm/node_modules/request/main.js:120:22)
npm ERR!     at Request.EventEmitter.emit (events.js:91:17)
npm ERR!     at Request.<anonymous> (/usr/local/lib/node_modules/npm/node_modules/request/main.js:648:16)
npm ERR!     at Request.EventEmitter.emit (events.js:115:20)
npm ERR!     at IncomingMessage.Request.start.self.req.self.httpModule.request.buffer (/usr/local/lib/node_modules/npm/node_modules/request/main.js:610:14)
npm ERR!     at IncomingMessage.EventEmitter.emit (events.js:115:20)
npm ERR!     at IncomingMessage._emitEnd (http.js:366:10)
npm ERR!     at HTTPParser.parserOnMessageComplete [as onMessageComplete] (http.js:149:23)
npm ERR!     at CleartextStream.socketOnData (http.js:1366:20)
npm ERR! If you need help, you may report this log at:
npm ERR!     <http://github.com/isaacs/npm/issues>
npm ERR! or email it to:
npm ERR!     <npm-@googlegroups.com>

npm ERR! System Linux 3.2.0-31-generic-pae
npm ERR! command "/usr/local/bin/node" "/usr/local/bin/npm" "install" "tap"
npm ERR! cwd /home/thaddeus
npm ERR! node -v v0.8.8
npm ERR! npm -v 1.1.59
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /home/thaddeus/npm-debug.log
npm ERR! not ok code 0