PDF.js の環境構築のエラー

Question

PDF.jsをvagrant上のcentOSにインストールしようとしたのですが，うまく行かず詰まってしまいました．みなさんのお力をお借りできれば大変ありがたいです．

環境:
MacBook OS10.11.3(EI Capitan)
Vagrant 1.8.1
centOS 6.7
参考サイト:
PDF.js

1. $ git clone git://github.com/mozilla/pdf.js.git

2. $ cd pdf.js

3. $ npm install

を実行したのですが 3. を実行した後以下のワーニングが出ました．

-------------------------------------中略---------------------------------
npm WARN optional dep failed, continuing fsevents@1.0.7
-------------------------------------中略---------------------------------
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/init-package-json requires glob@'^5.0.3' but will load
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/glob,
npm WARN unmet dependency which is version 6.0.3
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/read-package-json requires glob@'^5.0.3' but will load
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/glob,
npm WARN unmet dependency which is version 6.0.3
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/node-gyp/node_modules/npmlog/node_modules/gauge requires has-unicode@'^1.0.0' but will load
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/has-unicode,
npm WARN unmet dependency which is version 2.0.0
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/npm-install-checks/node_modules/npmlog/node_modules/gauge requires has-unicode@'^1.0.0' but will load
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/has-unicode,
npm WARN unmet dependency which is version 2.0.0
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/npmlog/node_modules/gauge requires has-unicode@'^1.0.0' but will load
npm WARN unmet dependency /home/vagrant/pdf.js/node_modules/wintersmith/node_modules/npm/node_modules/has-unicode,
npm WARN unmet dependency which is version 2.0.0

その後，PDF.js のドキュメント通り，

$ node make server

を実行して

http://localhost:8888/web/viewer.html

にブラウザでアクセスしたのですがエラーが帰ってきました．

３. を実行した後のワーニングが原因だと思うのですが，いかにして修正すればよいのでしょうか．ご教授よろしくお願い致します．