I have the exact same issue and it is truly starting to annoy me. Have not had any luck whatsoever with various "fixes".
I have tried to hex edit the saved games.
I reinstalled the game then tried to open the save.
Have done quite possibly ever possible graphical and sound alteration.
None of these things work.
I am totally grasping for straws here but I have a friend with a pretty similar system that doesn't have the glitch and the only difference I can find is that the first time I went to Dantoine I "revealed" myself and I wasn't able to complete the quest called "Redemption". I doubt this means much of anything, but I suppose it is worth comparing notes.
This is a seperate issue from the various graphical ATI problems and it would be great if we could keep it seperate.