You should use var %i = 1 and a while loop instead of a goto loop, it\'s shorter, easier, and leaves less room for error.
var %i = 1
while (%i <= 20) {
var %nick = $nick(#,%i)
if (%nick isop #) notice $nick 4,13 $+ %nick is an Op!
if (%nick ishop #) notice $nick 7,13 $+ %nick is a Halfop!
if (%nick isvoice #) notice $nick 11,13 $+ %nick is Voice!
if (%nick isreg #) notice $nick 9,13 $+ %nick is a regualar...
inc %i
}
}