I pulled the latest sylius code yesterday/a couple days ago (the whole standard bundle) to get fixes. I'm getting the error I put as the title of this question. I looked at the finite.yml file in the SyliusOrderBundle to make sure it was exactly the same as the finite.yml on github. Since I pulled everything, I should've also pulled whatever was necessary to make this change of setting callbacks in the config work. I've been googling but haven't found anyone else who observed this problem. I tried undoing whatever I thought would've affected this (e.g. uncommented my override of the order repository)and did another composer.phar update so that I had the latest of all the other bundles, but nothing's worked so far. Does anyone have any insight to this problem?
Turns out my composer.json wasn't properly merged with Sylius's updated one. After doing a correct merge, I was able to continue working out the kinks in my app.