4. Find the problem in my own code. It's been a while since I touched this, but at the same time I only needed to look in 2 fairly small source files and while some might be horrified that I chose C++ for this, it was an easy read. Good job, past me.
5. Found where I was doing a thing that could throw an exception and replaced the calls to that with a new function that wraps that in a try and does something reasonable on a caught exception.
6. Test that it's working again.