Comment 2 for bug 696883

I tried something I found on the web, and it worked.

"try removing /etc/btnx/btnx_manager and /etc/btnx_config_Default then running the config again
sudo rm /etc/btnx/btnx_manager
sudo rm btnx_config_Default sudo btnx-config If that does not work then try reinstalling the package
sudo apt-get --reinstall install btnx btnx-configthen
sudo btnx-config"

That's the post I found. But I couldn't go further than "sudo rm /etc/btnx/btnx_manager" and then I started btnx from the terminal, and it's OK. It works.

Apparently it came from the default config file it didn't find, and deleting "btnx_manager" seemed to solve the issue.
I'll try to make this all post resolved.