Problem installing with npm

[FredGr]

Hello,
I install sensor tag with npm install sensortag.
When I run the test-discover application I get 'Error: Cannot find module 'bluetooth-hci-socket'
So I try to install 'bluetooth-hci-socket with : npm install bluetooth-hci-socket
Then I get a lot of errors

npm ERR!
npm ERR! Please try running this command again as root/Administrator.

npm ERR! A complete log of this run can be found in:
npm ERR!
Any idea for a solution ?

Thanks