Can't rollback, it goes back 2 more errors then crashes. I'd actually saved in the middle of the initial sex scene with... whatsername, that shaman girl, back in 0.004, and then initially got frustrated when it broke in 0.005, although I didn't mention it until now. Here's the initial report:
Thank you for posting this information. Incredibly helpful and useful.
I couldn't replicate the error message, but I was able to replicate an error. My system automatically rolled back to the very start of the event (at the bottom of the hill) when loading a v0.004 save in v0.005. I've never witnessed this behavior before. Note this issue does not occur when saving at the exact same point in v0.005 and loading in v0.006, nor does it occur when saving at that point in v0.003 and then loading in v0.004. It's only the pre v0.005 and then post v0.005 that breaks it.
I assume that the entire system setup I'm using is able to rollback while your system is running into an error and unable to rollback. At least I'm able to replicate 'an' error being caused by the v0.005 update.
Although I'm not 100% on this, I'm fairly sure that the upgrade from Ren'Py version used from 7.4.3 to 7.5.3 breaks the saves. I did this version upgrade to increase compatitibility but it looks like instead it broke saves. That's a total bummer.
So, sadly, I do not have a fix for the broken save.
The only thing I can say is that I will not be upgrading the Ren'Py version used again. Thus, any saves made from here on out will be unaffected by this issue.
I wish I could say that I could salvage the save, but I'm not able to think of a way to do so. Sorry for that.