When you say "every" server, have you tried other networks than DALnet as all I see in your paste is DALnet servers. You might try
irc.undernet.org or
irc.quakenet.org and see if it's every network, if you haven't tried that already.
If you absolutely have to connect through a proxy then you need to edit mIRC's proxy settings. This is accessible at
ALT+O >
Connect >
Firewall. Extensive help can be found at
http://www.mirc.co.uk/help/proxies.html.
Regards,
