Lest anyone read this and fear that this is common: In my experience it isn't. Nor was it 4 or 5 years ago. I've never seen Coq crash at all, nor spit out any error message in French, and I was a full-time user for a while.
I stopped using Coq after that course and moved to other interests, but I'm relatively happy to know that, if I ever need Coq again, the chances for it to be the same PITA I remember are pretty low.
I might not ever need it anymore, but it's a small consolation to know that I don't need to fear that possibility.