Please submit a bug report on Github? I haven't gotten home from work yet and I have a lot of things I have to do tonight; my memory sometimes isn't so hot
If it also blows up for me I'll of course remember, but a Github bug report is the best reminder since my browser always loads Github.
So, on the way home I was doing some poking around and it looks like in 0.9.19 the calibre.ebooks.epub.fix package was removed. I depend on the Container class within that package, so I'll need to spend some time to figure out the best way to proceed. Either to copy the Container from 0.9.18 and modify it for my own local copy, use another Container if that class was just moved somewhere, or something more radical. Unfortunately this won't be a quick fix, so definitely no solution tonight, but if things go well by the end of the weekend maybe. Still put in a Github bug report though please