Checkpoint system fails constantly - is there any way to backup a checkpoint save?

[Sudz]

I can't keep doing this. I spent 2 full hours slowly working my way through the second scenario of the game (playing Solo), went through multiple checkpoints, finally quit the game and when I loaded it back up today ONCE AGAIN it started me way back at the beginning of the Cathedral of Resurrection. I've already gone through what I believe is about 80% of this level, twice, and it keeps failing to retain my checkpoint status and start me at the beginning of the same level.
I realize there is no player-selected save system (sadly, no reason to not allow this, thanks Rebellion), but is there some way I can find and back up the checkpoint saves that the game does automatically? Maybe if I can copy them off to another location I can put them back where they belong before I start playing again so I don't have to keep replaying the same parts of the game over and over without being able to progress. I just don't have enough free gaming time in the week to spend it re-doing parts of a game I've already been through.