Help with the new UXP createInsertProjectItemAction() method. "Script Action failed to execute"

Hi. I've been trying to use the new UXP createInsertProjectItemAction() method to insert a clip into my main sequence's timeline, but I can't seem to get it to work. I'm getting the following error ("Script Action failed to execute."):

Here's the Adobe documentation page for that method.

Here's a sample with all of the required parameters:

SequenceEditor.createInsertProjectItemAction(projectItem, TickTime, videoTrackIndex, audioTrackIndex, limitShift);

Below is the entirety of my code. The error happens at line 19, and execution of the script stops before it even gets to the executeAction() function (line 29), so I don't think that's the problem. For context, my Premiere project just consists of a sequence called "Main Sequence" and a video clip called "Iceberg.MOV".

1  const ppro = require("premierepro");
2 
3  async function insertItem() {
4    try {
5         const project = await ppro.Project.getActiveProject();
6         const rootItem = await project.getRootItem();
7         const items = await rootItem.getItems();
8         const mainSequence = await project.getActiveSequence();
9         const editor = await ppro.SequenceEditor.getEditor(mainSequence);
10        const insertionTime = await ppro.TickTime.createWithSeconds(2);
11        var itemToInsert;
12        
13        // Specify the item you want to insert into the timeline
14        items.forEach(element => {
15            if (element.name == "Iceberg.MOV") itemToInsert = element;
16        });
17
18        // Create the insertion Action
19        actInsertProjItem = await editor.createInsertProjectItemAction(itemToInsert, insertionTime, 1, 1, false);
20        
21        // Execute the insertion Action
22        executeAction(project, actInsertProjItem);
23
24    } catch (err) {
25        console.error(err);
26    }
27  }
28
29  function executeAction(project, theAction) {
30     try {
31        project.lockedAccess(() => {
32            project.executeTransaction ((compoundAction) => {
33                compoundAction.addAction(theAction);
34            })
35        });
36    } catch (err) {
37        console.error(err);
38    }
39  }
40
41  document.querySelector("#btnPopulate").addEventListener("click", insertItem);

Things I've already investigated:

• Checked to make sure I'm running the latest version of the Premiere Pro beta app (25.3.0 build 33).
• My seqEditor variable is of the right type (SequenceEditor object).
• All of the parameters passed in the createInsertProjectItemAction() method are of the right type (projectItem, TickTime, numbers, booleans).
• Tried changing the values of the videoTrackIndex, audioTrackIndex parameters to different numbers.
• Tried changing the value of the limitShift parameter (true/false, 0/1 etc).
• Tried different types of items to insert (video clip, sequence, adjustment layer, color matte etc).
• I've also tried searching online for help, but Google literally returns zero pages discussing this method except for the Adobe documentation page and a Creative Cloud Developer forum page announcing its release 10 days ago (March 19, 2025).

If you have any ideas on how I can get it to work, or if you can spot any errors in my code please let me know. Thanks!