We were looking into this bug on and off for quite some time in the Tyranny. Last year, I put forth a theory that it only occurs after you've submitted a game to the Metaverse and that by deleting the .xml files found in the My Games\GC2DarkAvatar\Metaverse folder (post game submission), that the crashes significantly decrease in number. This has helped a number of people so far. The data isn't conclusive, so we haven't posted it widely, but it's known both inside and outside of the Tyranny. (We haven't revisited the problem until recently as deleting the .xmls seems to help and it's not too inconvenient of a bug anymore).
There are a few people that don't see this bug at all. As far as I can tell, these people are using Windows Vista for the most part.
I have 3 computers with separate GalCiv2 installations running on XP and all 3 experience the CTRL-N crash. 2 of these machines have Impulse and are updated to the newest versions and the other has SDC and is updated only to SDC's max of DA 1.8g. The SDC machine has the Gold Edition on it. One Impulse machine started out as DL and later had the DA and TA expansions added. The other machine started as a base DL machine, but I bought the expansions immediately upon installation.
@Mystikmind - The reverting to "fool" via CTRL-N is another issue, but it can be easily detected by looking at your income at the opening planetary screen. Look at it when first opening it and then after hitting CTRL-N. If your income goes high, your game difficulty has been reset to Cakewalk. This is why the AI reverts to "fool".
I hope this helps in both cases.
