Hi nitrous,
I tried running the app in OS X 1.6.8 (snow leopard). But it crashes after I select the dump file name in (File->new dump). It prints segmentation fault at the prompt.
I was able to track the error to self.update() call at the end Application.load_dump function at gui.py file (line 217). It actually inconsistent, when I place some print around update() call, it works some time. Anyway, it ran fine when I commented the self.update() line out. I think this function updates window visual after update_button state is set to normal, isn't it? I don't have a better idea of what it could be. But I am happy to test on OS X 1.6.8 if you have any idea.
If anyone is interested I posted a version with the alteration described above
https://www.dropbox.com/sh/cyql48n834n9sfq/VWuOLxYA79Cheers