set pageNumbers to text returned of (display dialog "Seitennummern eingeben:" default answer "") 
 
set AppleScript's text item delimiters to " " 
set tmpList to every text item of pageNumbers as list 
set AppleScript's text item delimiters to {""} 
set tmpString to every text item of tmpList as string 
set AppleScript's text item delimiters to "," 
set defList to every text item of tmpString as list 
set AppleScript's text item delimiters to {""} 
 
tell application "Adobe InDesign CS4" 
  activate 
  -- die GREP-Vorgaben löschen ...  
  set find what of find grep preferences to nothing 
  set change to of change grep preferences to nothing 
   
  -- das GREP-Muster definieren  
  set find what of find grep preferences to "~y(ab )?[0-9]+ Min." 
  set change to of change grep preferences to "" 
   
  -- das Suchen/Ersetzen ausführen  
  tell document 1 
    repeat with p from 1 to count of defList 
      set curNumber to item p of defList 
      try 
        tell page curNumber 
          tell every text frame 
            change grep 
          end tell 
        end tell 
      end try 
    end repeat 
  end tell 
   
  -- die GREP-Vorgaben zurücksetzen ...  
  set find what of find grep preferences to nothing 
  set change to of change grep preferences to nothing 
   
  -- die Anwenderin benachrichtigen  
  display dialog "Fertig." buttons "OK" default button 1 with icon 1 giving up after 1 
   
end tell 

set defList to {"66", "77", "78"}