Hi Dave
I'm very pleased you're using Node as well, firstly because I'm excited to see what you'll come up with when given this new palette of possibilities, and secondly because I think you'll be in a great position to help others through the journey you've undergone.
The error trace implies that you've somehow got a tiddler in your wiki folder that does not have a properly formed title. It's not clear how that happened, but it does suggest a strategy for tracking it down.
Can you make an empty copy of your wiki folder, and then gradually add back in the tiddlers from your current folder? You'll need to restart TiddlyWiki between each attempt. By trial and error you should be able to track down if there's a specific tiddler that is causing the problem.
Best wishes
Jeremy