Can you access from linuxmce itself? What about the internal network 192.168.80.***? That will be from your 2nd nic. I cannot remember if web-admin works on outside network from default but in web-admin wizard (one of the menu's I'm not at home so cannot check) is outside access link try ticking box for port 80 and try again.
Have a hunt on wiki for more info and security issues of doing this.