If it helps, whatever problem I was having starting a new game has gone away and I was able to start.
I deleted my Ashes of Erebus folder and then re-downloaded the latest SVN. I tried a Play Now game with the default modules and was able to start. I exited to desktop, used the launcher to choose which modules I wanted (activating some, disabling others), and again was able to start a Play Now game.
Specifically, I'm using these modules: Advanced Workers, Black Duke, Chislev Expansion, Churel, CrimeBalanceTest, Dao, Dural, Dwarves, Emergent Leaders, Everchanging, Flight of Drakes, Fortifications, Frozen, Lizard Art Fix, Magister Ashes, MOM Buildings, More Events, Node Yields, Noggormotha, One Potion, PPQ Effects, PPQ Flavor, PPQ Navy, and Scion Healthcare.
I exited to desktop again, used the launcher to launch AoE, kept the same modules active, then created a Custom Game using my preferred settings, and was able to start. So far, so good.
So looks like I was mistaken about the Crime Balance Test and One Potion modules possibly causing a crash on startup.