You got an firewall blocking you. If you have Windows Firewall, go to firewall options, find IRC and set it to option "UNBLOCK" (the Firewall will grant access to internet", or if you have an other firewall, right click IRC.exe (not the shortcut) and try to configure it- if that doen't work, open firewall options and set "UNBLOCK" to grant access to IRC.
Oh, if anything of this works, i have no idea what else to do. :'(