Yzmo

This is a good resource for learning GtkRadiant which I contributed to a while ago. I figured I might as well link to it here, it might be useful. It could also be a good place for more people to contribute.

https://en.wikibooks.org/wiki/GtkRadiant

My guess is that it has something to do with the NPCs. Try adding them one by one and see if you can find the one causing the trouble.

Does it crash when you look in a certain direction or do something specific?

If you can't see any textures at all make sure the paths are set correctly in the preferences.

I'm quite sure there is a way to make the surface transparent.. Check a water texture for the specific keyword. Oh and if you're really lazy you could just make a transparent png and use that xD

There's no real reason for Microsoft to drop 32-bit compatibility any time soon. Just think about all the companies using legacy 32-bit stuff. They'd make themselves extremely unpopular while also loosing a lot of sales. I regret to say that I believe the JKA community and general interest in the game will die much earlier than the possibility to run it.