I installed Node manually this way which worked perfect. Then continued with NodeBB guide & NPM install worked
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.32.0/install.sh | bash
Reboot machine
. ~/.nvm/nvm.sh
Determine what version of Node to install
nvm install 6.10.3
check version is installed by running
node -e "console.log('Running Node.js ' + process.version)"
