EventMachine: "`start_tcp_server': no acceptor (port is in use or requires root privileges)"

When I try and run the server with EventMachine::run I keep getting the error saying that the port is in use. This started ever since I ran the server in the background with the command nohup.

I am pretty sure I have killed the process I started:

• I found the ruby process with ps, and killed it. It no longer shows up.
• I also ran lsof -i :8081 (8081 is the port I ran it on) and nothing shows up.
• Finally, I have changed the port in the ruby program a number of times to obscure ports, and still get the error!

I also thought it could be the lack of me being the root user, so tried it as root to no avail.

I have also restarted the server.

Please let me know if there's anything else I can try.

Note: this is on debian.

I have finally figured it out: it was actually the IP address I was binding to that was incorrect!

So essentially it is a very misleading error message, and if you get it, check the IP address too.