grunt-browser-sync won't install

i'm willing to use the grunt-browser-sync plugin on my project but i can't, because it won't install.

when i type

npm install grunt-browser-sync --save-dev

on my terminal on the root folder of my project, the plugin starts installing and then it gives me all kind of errors.

i tried running it anyway, and here's what the terminal says:

and the npm module folder of the plugin looks kind of "empty" to me:

i'm really no big expert of npm, grunt etc. i have a really hard time figuring out what to do in these situations so help will be greatly appreciated :) i really need to have this working

thanks!