module.js:338 throw err in node.js
It seems like the script has an unmet dependency - meaning you have to install the module "merge-descriptors" first.
It also seems like the script is using "express" (and "merge-descriptors" actually looks like a dependency of "express") - because this didn't throw an error some dependencies seem to be installed already.
So you could try to install the missing ones via npm install or npm update.
Update: According to npmjs.org "merge-descriptors" is an dependency of "express". Looking at your stacktrace shows that you have "express" installed globally - so you should try npm update -g
If that doesn't solve your problem you should have a look at this question.
I see this when the module install order is not perfect, or multiple modules exist.
npm update sorts this out deprecating the incorrect versions.