You appear to want to use %sl and not %var so you can change that where it is blue
The orange 400 is a length of message control, most (all?) networks well send notices this length, if yours doesnt then reduce it, or if the contents of these variables is large then reduce it.

* global var %sLchannel must already be set by u elsewhere!

Code:
on *:TEXT:@wmfind *:%sLchannel:{
  notice $nick ** Results for $+(,$2-,) are as follows... 
  var %text 
  var %i = 1
  while ($var([color:blue]%var[/color]*,%i)) {
    if ($2- isin $($v1,2)) { var %text = $update(%text,$v2) }
    inc %i
  }
  $update(%text)
}
alias -l update {
  var %msg.length = [color:orange]400[/color] 
  var %text
  if ($0 == 1) {
    if     (!$len($1)) { notice $nick No Matches Found. }
    elseif ($1 != &)   { notice $nick $1 }
  } 
  else {
    var %text = $1 $2
    if ($len(%text) > %msg.length) { notice $nick %text | var %text = & }
  }
  return %text
}


Code was tested and ran fine on mirc v6.16