Help with an emergency: The script went wrong at a critical time.

[dublove]

Here's the script by Peter Kahrel from the forums

I use this script to label specific characters on different columns with ABC.

The same file was available for use a year ago.

Now suddenly it prompts an error.

Some scripts will not work after ID upgrade？
Help to see it. Thank you very much.

Initial address:

https://community.adobe.com/t5/indesign-discussions/what-is-the-method-to-identify-which-column-a-ce... 

cstyles = [
  app.activeDocument.characterStyles.item('A'),
  app.activeDocument.characterStyles.item('B'),
  app.activeDocument.characterStyles.item('C'),
];

app.findGrepPreferences = null;
app.findGrepPreferences.appliedCharacterStyle  
  = app.activeDocument.characterStyles.item ('AAA');
  
instances = app.activeDocument.findGrep();

for (i = 0; i < instances.length; i++) {
  columnIndex = instances[i].parentStory.insertionPoints.itemByRange (
    instances[i].parentTextFrames[0].insertionPoints[0].index,
    instances[i].index
  ).textColumns.length-1;
  instances[i].appliedCharacterStyle = cstyles[columnIndex];
}