Just moving the inc %y outside of the if statement would also work:

Code:
while %y <= $did(scriptsend,1).lines {
  if ($did(scriptsend,1,%y).len) || ($did(scriptsend,1,%y) == $chr(32)) {      
    msg $snick($active,%x) $did(scriptsend,1,%y)
  }
  inc %y
}