Ahh, this is interesting. It looks like something IS using that port:
Code:
edolfo@edolfo-server:~$ sudo netstat -ap | grep 5999
tcp 0 0 *:5999 *:* LISTEN 13808/MiniLogin.exe
udp 0 0 *:5999 *:* 13808/MiniLogin.exe
Doh. Good idea though, not sure why I didn't think of that. Guess it's one of those days...