The game crashes in plaza of the sun when I attempt to go to another part of the level (just after the river of life that you're warned not to enter).

What do you make of the crash error in the screenshot?

Thanks

Not sure, to be honest. Also, Hexen 2 has a great sourceport called Hammer of Thyrion, which you should be using to play the game if you aren't already:

http://uhexen2.sourceforge.net/

http://uhexen2.sourceforge.net/readme.html
http://uhexen2.sourceforge.net/music.html

I looked closer at the screenshot and realised it's trying to load the next area from some Temp folder! Why on earth would it do that? I even tried putting various/all the game files in that folder and still nothing happened.