I am trying to install node_module but getting following error:
For example:npm install grunt-preprocess
D:\\grunt_pre>npm install grunt-preproces
I'm getting the exact same thing. Either the module exists but the actual download repository is down or there is a problem with npm at the moment. Try again in a few days or report it to the github link.
Edit:
The error you are getting is a timeout from their server or your connection. It could be because you are behind a firewall/proxy that is stopping your connections.