I am having following errors while installing MM

Cloning MagicMirror Done! Installing dependencies ... npm WARN prefer global coffeescript@1.10.0 should be installed with -g npm WARN prefer global jsonlint@1.6.2 should be installed with -g > uws@0.14.5 install /home/pi/MagicMirror/node_modules/uws > node-gyp rebuild > build_log.txt 2>&1 || exit 0 Unable to install dependencies! pi@raspberrypi:~ $