For your info, if you need to know troubles with app, just run it from terminal. Yes, you are right, exterminator stops working. When I ran it from terminal, it "says" you need psutil. As I know the exterminator is written in python, you need to install this package:
sudo apt-get install python-psutil
(Maybe we need to rebuild the package with psutil dependancy)
Yes, it is lightweight, but from my POV it is not very reliable browser. I ceased using it years ago because of many crashes and some GUI discomfort. Better light performance and good stability offered me qupzilla.