Simplified to just include the necessary nodes that contribute to the crash.
1. Open the file
2. Switch to the 'Renderers' button along the top
Result: Crash (Terragen disappears)
I think it has something to do with using the combination of the Subtract node and the Merge node, because if I use any other combination, it seems fine. Plus if the 'Mix to A' slider in the Merge node is anything other than 0 and 1, it will crash when selecting the 'Renderers' button along the top.
Cheers.