Users often think that Microsoft's runtime error alert communicates useful information, that we'll be able to diagnose the issue when they say, "I clicked on 'Go' and got a runtime error 555. What's wrong?" Unfortunately, about all we know from that message is that Word is probably having a difficulty addressing or locating a file. Not much help there.
So, if you should receive a runtime error message, treat that as the start of the diagnosis process, not the end.
Look for patterns:
Does this happen only (or mostly!) when using Master Lists?
Does it happen on every command, or just one?
Does it happen with every document, or just one?
Is it a new issue, which hasn't happened in previous uses?
Using this approach helps narrow the issue and provides clues as to its cause.
Finally, use TheFormTool to drop MSFT a note suggesting that as a leader in digital communication, they might consider translating their error message codes to English or the local language in use. While that won't help the diagnosis and fix problem directly, it might focus attention on how little MSFT has done to make the process user-friendly.