Ryan, try replacing my modification in place of the original and see how it goes:

if (%t_nick isop %t_chan) && ($regex(%t_2,/^o(n|ff)$/iS)) {
      if ($regml(1) == n) {
        set $+(%,twitter_,%t_chan) ON
        .notice %t_nick !twitter script is now ON
        twitter_cleanup 
      }
      else {
        set $+(%,twitter_,%t_chan) OFF
        .notice %t_nick !twitter script is now OFF
        twitter_cleanup     
      }
    } ;end of %t_on/off
  ;--- Checks if twitter is suppost to be OFF for the channel --
  if ($($+(%,twitter_,%t_chan),2) == OFF) {
    twitter_cleanup
    halt
  }