It CTD's in a loaded save game after I hit end turn usually between 1 to 3 times during the AI phase before cutting to a black screen and dieing and when I start a new campaign the opening movie plays then the loading bar completely loads then it goes to a black screen and dies.

I did attempt it with a single archer first and it worked with no problems (not that I played for many turns since it was just a test) before I attempted to do it with all the units.

I didn't use the replace all function I used notepad or notepad++ (I've gone over and retried things in both) and used copy and paste to change each line one at a time just to be sure.