Não tenho o seu ambiente e não posso testar, mas este excerto da FAQ da gphoto parece dizer que isso pode ser uma questão de permissões, em vez de algum programa monopolizando a interface.
A seguinte citação contém um link para o capítulo Configurar permissões para portas USB que você pode verificar .
Why do I get the error message "Could not claim the USB device"?
You have to make sure that no such kernel module is loaded and that you have set up the permissions on your USB device correctly, such that you have (non-root) write access to the camera device. How to set this up, is described at Section 4.3, Setting up permissions for USB ports.
This can also happen with cameras that works as USB Mass Storage devices. A notable example is if you have an Olympus Camera that gets auto-detected as an Olympus C-2040Z. In this case, you can try, if you run Linux, to remove the usb-storage kernel module and attempt to use libgphoto2 with it. But, unless you want to control the camera (not all the model supports it), it is not a recommended solution. Keeps using USB Mass Storage. Some of these Olympus supports to be switched to "PC Control" mode in order to be remote controlled with an external program like one using libgphoto2.