You should really check for $dns().nick so if you dns an address\ip you don't end up with
%_ip 209.240.130.48
%_adress mirc.com
* DNS Result: Nick: / Adress: mirc.com / IP: 209.240.130.48

Code:
on *:dns:{
[color:blue]  if $dns(1).nick {[/color]
    set $+(%,$v1,_ip) $dns(1).ip
    set $+(%,$v1,_adress) $dns(1).addr
    echo 4 -a * DNS Result:3 Nick: $v1 / Adress: $($+(%,$v1,_adress),2) / IP: $($+(%,$v1,_ip),2)
[color:blue]  }[/color]
}

Now you don't need to set %nick
Code:
menu nicklist {
  -
  Check Ip From $$1:.dns $$1
  -
}