I'm having an issue - I made a little mission involving a Super-Juggernaut SD Dante and Vishan Preserver. When the Preserver was killed my game crashed and closed instantaneously. I went to FRED to see what's up and noticed that I cannot delete either the Dante or the Preserver. I can change their names, ship classes, orders, wings, etc. but I cannot delete these ships.
I went through and deleted all events and orders related to these ships, then I got frustrated and deleted all the events, orders, and other ships/objects (aside from the player ship) in the entire mission. I still cannot delete these ships from FRED (regardless of what I have since changed their classes to), and when they go down in-game (once again, regardless of ship class) they take the program down with them...
I'm using 3.6.12 RC4 for both FRED and Freespace2. I haven't got war in heaven yet, though.