osx系统，安装0.10.5,通过pkg包安装，npm安装的有n，但之后就报错了。请教是什么原因。

sudo npm install -g supervisor module.js:340 throw err; ^

Error: Cannot find module 'npmlog’ at Function.Module._resolveFilename (module.js:338:15) at Function.Module._load (module.js:280:25) at Module.require (module.js:364:17) at require (module.js:380:17) at /usr/local/bin/npm:19:11 at Object.<anonymous> (/usr/local/bin/npm:87:3) at Module._compile (module.js:456:26) at Object.Module._extensions…js (module.js:474:10) at Module.load (module.js:356:32) at Function.Module._load (module.js:312:12)