I also get the error when setting a non-default running speed. Currently using Factorio 0.17.50 and Big Bags v 1.0.30

Is this code on github or somewhere else?

Sorry, I found the problem, but this still is odd:
It seems like the research tree has changed a lot since 0.16, so many basic technologies have not been unlocked.

One of them was "Fast inserter" and another was "green science" and so on. Very cheap and fast to research, but unexpected.

In a daring move, I upgraded from 0.16 to 0.17.31. I could have chosen a newer version, but decided that I didn't want to take too much risk.

When continuing my saved game, I no longer find the option to craft fast inserters.
Is that a bug, or does continuing a saved game in another version create ...