Also bei mir tritt der Fehler nur auf, wenn Safari im Full-Screen Mode ist...

bitte ersetze den ganzen System Events block probehalber durch

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  1. tell application "System Events"
  2.   tell process "Safari"
  3.     try
  4.       set theWindow to 1st window whose description of toolbar 1 of group 1 is "toolbar"
  5.       set textValue to value of text field 1 of group 3 of toolbar 1 of group 1 of theWindow
  6.     on error
  7.       set theWindow to 1st window whose description of toolbar 1 is "toolbar"
  8.       set textValue to value of text field 1 of group 3 of toolbar 1 of theWindow
  9.     end try
  10.    
  11.   end tell
  12. end tell
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Gruss

Stefan