The problem: while using nvm to install Node.js I was able to install the version of Node.js I need, but nvm does not install npm auto
nvm
npm
Try going to Window -> Preferences -> Nodeclipse and unchecking the box that says "find node on PATH...". Then make sure the "Node.js path" below is set to the location of the node.exe file (for me it was C:\Program Files (x86)\nodejs\node.exe).