Version: revision 570312 (using KDE KDE 3.5.4) /ignore nick [Ignore] Added nick!* to your ignore list. /unignore nick [Error] No such ignore: nick /unignore nick!* [Ignore] Removed nick!* from your ignore list /ban nick [Mode] You set a ban on nick!*@*. /unban nick [Mode] You remove the ban on nick!*@*. So, /unignore nick should just work too.
Fixed in SVN.