How to resolve playback errors with seemingly no cause?

Some time ago, I posted a question about scrolling typewriter text in a dialogue box. While the answers were helpful, it, unfortunately, didn’t provide me with what I needed. After continuing my search 2 days ago, I found a tutorial from 2015 (which I believe may be the cause of my problem.) that had literally exactly what I needed, and it worked.

However, while everything runs perfectly in the editor, after the textboxes have loaded, the logs prompt me with an error, which I, unfortunately, can’t read. I’ve tried numerous things to fix it but everything has either broken the system (in sometimes hilarious ways.) or just made the text not load at all. Sadly, the tutorial obviously never runs into this issue, and I copied the movements 1:1, I’m quite certain.

For reference, [this is the tutorial I was following.][1]
And this was the error message:

Blueprint Runtime Error: "Attempted to access index 28 from array

CallFunc_GetCharacterArrayFromString_ReturnValue of length 28".

Blueprint: Finn_1WhatNoise (< This is the name of my textbox widget.)

Function: Execute Ubergraph Finn 1What Noise

Graph:Typewriter (< This is the Macro containing the Typewriter code.)

Node: Assign (< Since there’s about a million different “Assign” nodes in the graph, I’ve highlighted the one in this image.)

I doubt this would be much use, but this is the full graph.

While I don’t consider this a massive issue, I’d like to be able to boot up my game for testing and not worry about some fatal error going on in the background. If anyone can help out, I’d really appreciate it. Also, do let me know if you need any other info from me. Thanks in advance.