Fix instructions in docs. Fixes #174.

docs/client/concepts.html

@@ -544,7 +544,7 @@ created on.  To run on a different platform, you'll need to rebuild
 the native packages included in the bundle.  To do that, make sure you
 have <code>npm</code> available, and run the following:
 
-    $ cd bundle/server
+    $ cd bundle/server/node_modules
     $ rm -r fibers
     $ npm install fibers@0.6.5
 {{/warning}}