Cannot find module 'npm'

[Pumpapa]

This is beyond my understanding. Obviously npm is installed

$ node server.js
=================================================================
=  Please ensure that you set the default write concern for the database by setting    
. . . 
=  This message will disappear when the default safe is set on the driver Db           =
================================================================

Connecting to MongoDB...

/Users/pum/node_modules/mongodb/lib/mongodb/db.js:279
          throw err;
                ^
Error: Cannot find module 'npm'