I loaded a challenge and accidentally accepted it. I have no opponent. It’s not set up to play myself. How to delete?

Why don’t all players just play open password? Are they afraid of a better player coming along to teach them strategy and tactics? I’m not claiming to be any kind of expert, I just want to play against real people! All my challenges are open! Like real war, one learns from losing! I encourage all of...

DF Campaign game is playable until option to refit/combat comes up. When I choose refit, the game inevitably crashes after I've placed my mines as the Commonwealth player. Frustrating to say the least.