explain-this-error.txt
Error, full text:
<paste>

The code that produced it:
<paste>

In this order:
1. What this error means in general — in plain English, no jargon.
2. What specifically triggered it in MY code, pointing at the line.
3. The fix.
4. What I could have checked to spot this myself next time.

If you cannot tell from what I've given you, say what else you need.

Step 4 is the one that compounds. Errors repeat; the second time you meet this one you want to fix it in thirty seconds, not thirty minutes.