Yes, the CMS course is one of the old ones that I keep wanting to retire, and people then complain when I remove it!
It is hard to debug visually because as you know, the smallest thing could be causing the error. Have you tried isolating elements of the code, step by step testing where things break?
That said, if you've finished the foundations courses, and followed my instructions for the project - just do the first few simple ones, I would say use a more modern CMS building tutorial online. There are probably many just on YouTube.
But better yet, just jump into some contract work now ... learn as you earn!
Hope that helps!