"Upgrading Perl" is seldom the right choice, and if you upgrade and nothing changes chances are that you upgraded the wrong thing...

My guess is that something with the network/routing/name resolution on the box is wrong. Did you try connecting to irc manually, through telnet and through a real irc client to debug the connection?

I'm not sure if Perl 5.8.2 is the currently distributed version of Perl in Debian, but be aware that it is a bad idea to change your system Perl, especially for Debian, as many of their utilities rely on Perl and special Debian modules that they don't have on CPAN.