Amazon EC2 Error: listen EACCES 0.0.0.0:80
You probably have to run your node.js script with sudo as you want to listen on port 80.
You cannot run a process that listens on low ports (below 1024) without root privileges.
You either try to run as sudo, as stated above, or start to use a reverse proxy (nginx for instance), start the process on another port and use the reverse proxy to forward the calls from port 80 to whatever port you started the process on.
The error code EACCES means you don't have proper permissions to run applications on that port. On Linux systems, any port below 1024 requires root access.