title: TypeError: Arguments to path.join must be strings
body: <p>when I write    </p>
  
  <pre><code>&lt;link rel='stylesheet' href='/stylesheets/style.less' &gt;
  </code></pre>
  
  <p>in index.ejs ,my browser work  but  .less not work no style show.
  when I write </p>
  
  <pre><code> &lt;link rel='stylesheet' href='/stylesheets/style.css' &gt;  
  </code></pre>
  
  <p>in index.ejs ,my browser error.The error is :</p>
  
  <pre><code>GET http://localhost:3000/stylesheets/style.css 500 (Internal Server Error) 
  </code></pre>
  
  <p>and  in the cmd show :</p>
  
  <pre><code>TypeError: Arguments to path.join must be strings
      at f (path.js:204:15)
      at Object.filter (native)
      at Object.exports.join (path.js:209:40)
      at Object.handle (E:\nodejsApp\jsmoudle\node_modules\less-middleware\lib\middleware.js:128:26)
      at next (E:\nodejsApp\jsmoudle\node_modules\express\node_modules\connect\lib\proto.js:193:15)
      at pass (E:\nodejsApp\jsmoudle\node_modules\express\lib\router\index.js:110:24)
      at Router._dispatch (E:\nodejsApp\jsmoudle\node_modules\express\lib\router\index.js:173:5)
      at Object.router (E:\nodejsApp\jsmoudle\node_modules\express\lib\router\index.js:33:10)
      at next (E:\nodejsApp\jsmoudle\node_modules\express\node_modules\connect\lib\proto.js:193:15)
      at Object.methodOverride [as handle] (E:\nodejsApp\jsmoudle\node_modules\express\node_modules\connect\lib\middleware\methodOverride.js:48:5)
  GET /stylesheets/style.css 500 12ms
  GET /javascripts/index.js 304 11ms
  </code></pre>
  
  <p>this is  package.json</p>
  
  <pre><code>{
    "name": "application-name",
    "version": "0.0.1",
    "private": true,
    "scripts": {
      "start": "node app.js"
    },
    "dependencies": {
      "express": "3.4.8",
      "ejs": "*",
      "less-middleware": "*"
    }
  }
  </code></pre>
  
  <p>I don't know .less can pass, .css can't pass</p>