Ok, I see in the log that the recent errors are from the contracts screen (also used for political deals once you've picked an overall category) and related to something working with a Tech type (though not necessarily, that's just the code that hit the error).
But when I load the save and poke around a bunch of contracts screens and political deal screens, particularly the options that have you pick a tech, I get no errors.
Can you try loading the save and seeing if you get an error? If so, what precisely did you do right before it happened?