node error cannot find module already installed

Question

[root@zexu websocket_start]# npm ls -g installed
npm WARN ls doesn't take positional args. Try the 'search' command
npm WARN websocket-server@1.4.04 package.json: bugs['web'] should probably be bugs['url']
/usr/lib
├─┬ npm@1.1.2 
│ ├── abbrev@1.0.3 
│ ├── block-stream@0.0.5 
│ ├── fast-list@1.0.2 
│ ├── fstream@0.1.12 
│ ├── graceful-fs@1.1.5 
│ ├── inherits@1.0.0 
│ ├── ini@1.0.2 
│ ├── lru-cache@1.0.5 
│ ├── minimatch@0.1.5 
│ ├── mkdirp@0.3.0 
│ ├── node-uuid@1.3.3 
│ ├── nopt@1.0.10 
│ ├── proto-list@1.0.0 
│ ├── read@0.0.1 
│ ├── request@2.9.151 
│ ├── rimraf@2.0.1 
│ ├── semver@1.0.13 
│ ├── slide@1.1.3 
│ ├── tar@0.1.12 
│ └── which@1.0.3 
└── websocket-server@1.4.04 
[root@zexu websocket_start]# npm ls  installed
npm WARN ls doesn't take positional args. Try the 'search' command
/home/qonco/workspace/JS/websocket_start
(empty)
[root@zexu websocket_start]# node
> require("websocket-server");
Error: Cannot find module 'websocket-server'
    at Function._resolveFilename (module.js:332:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:354:17)
    at require (module.js:370:17)
    at repl:1:1
    at REPLServer.eval (repl.js:80:21)
    at repl.js:190:20
    at REPLServer.eval (repl.js:87:5)
    at Interface. (repl.js:182:12)
    at Interface.emit (events.js:67:17)
> 

Answer 1

Have you installed the module with the -g option? I think that not every module is meant to be installed globally, instead, try installing it locally for the project you are creating (npm install), and check if the error persists.

Answer 2

You have installed the module globally. Go to your app and try this to link the global to your application folder. Like so:

sudo npm link <MODULeNAME>