Thanks for reporting the bugs!
I remember someone mentioning the dialogue freezing issue before — it was mainly caused by a typo in the code (if I recall correctly, one of Willa's compliments got stuck in a never-ending loop). That bug has already been fixed, though I’m not entirely sure if the fix made it into the current public version. If not, it should be addressed in the upcoming public update.
Next month's update will also include optimized shaders and texture maps, which should significantly reduce GPU load. However, if the fatal error still shows up, it might mean the textures still aren't downscaled enough — or that something else in the program is putting too much strain on the CPU. Just a guess for now, but I’ll be keeping a close eye on it as the next update comes together.