If you need to execute an Automator workflow from an AppleScript, have the application "Atomator Launcher" open the saved workflow document.
A sample code snippet would look something like this:
tell application "Automator Launcher"
open "... path to saved workflow document ..."
end tell
The workflow will execute without opening Automator, and you get the workflow status in the menu bar. As far as I can tell, the "Automator Launcher" is a core application that does not appear to be scriptable. It won't even show up on a Finder level search.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050512170841120