Idle and problems

I am glad to idle with my new script. Each time my script idle timer goes thru the script, I have an answer that comes up in a display dialog. Great to see this dialog, but the script runs into error when the screen effects goes active.
My question is how can I tell thru my scripting can I tell if


on idle 
   tell app "System Preferences" -- or would i direct it to system events?
      if Screen Effects is not running then --- just an outta my head thought, DOE...
       tell current application to  display dialog <My idle dialog>
      end if
   end tell
return 60 * 60 -- minutes X seconds
end idle

The Above code is just what i think I might have to do… but something tells me about system events :?

on idle
  tell application "Finder"
    process "ScreenSaverEngine" exists
  end tell
  if the result is false then
    tell application (path to frontmost application as string)
      display dialog "Boo!"
    end tell
  end if
  return hours
end idle

Thanks Nigel. That’s works wicked! :lol: