I suggest using this: (Works better and always returns something.)

 on $*:text:/^[.!@]topic\b/iS:#: {
  if ($nick isop $chan) && ($address($nick,3) == $address($me) {
    .cs set $chan topiclock off
    topic $chan $2-
    return
  }

  elseif ($nick !isop $chan) && ($address($nick,3) != $address($me) {
    notice $nick Error: You have to be a op to use this command.
     return
      }

if ($2 == $null) {
notice $nick Error: Please provide a topic (Syntax: !topic (Topic)
return
}