I've found a situation that seems to always result in Blender crashing when exporting with the plugin.
Hmmm, hmmm... yes, you're right.
It's funny, I never tested to move the script to the scripts folder yet, my first thought was "what Export Button ?!"
(I always loaded it into Blender's text editor and started it there, but it's the same result.)
Anyway - that's IMHO not the problem, neither is it the renaming itself, although you nicely tracked it down to something I could reconstruct, thanks for that. Another funny test: run a windows shell window and start Blender from there. In this case it does not crash for me. (But it crashed when I closed the Blender window, argh!)
I can't say too much about it yet, I had thousands of crashes while testing already and it only went a little better since I went back to Python 2.3 ! If we were in older DOS times I would try to increase the stack memory for Blender, which could explain it reacts differently when running it from a shell, but... I'm clueless up to now.
I'll try to have a deeper look into after christmas, but I've got the bad feeling that there are still heavy memory leaks in Blender's Python integration... or I just don't know how to handle these things yet.
Edit:
Blender 2.36 is out. Installed it, copied the script, ran it. Worked. Maybe you could also have a try with 2.36, some python bugs (the fixed crash bug on "meshes with edges" and some other bug in the "Mathutils.Euler" could be quite responsible for this) were fixed as well. But it still could be some coincidence, sometimes 2.35 didn't crash now neither.