I'm trying to install copy.com's client on Ubuntu 13.10 but when I do, I get the following error message:

Gtk-Message: Failed to load module "canberra-gtk-module"

(CopyAgent:4430): LIBDBUSMENU-GTK-CRITICAL **: watch_submenu: assertion 'GTK_IS_MENU_SHELL(menu)' failed

From there, it initially appears that the Copy client installs correctly. I am prompted to login and their icon shows up in the task bar. However, sync does not work properly. Items placed in my Copy folder on other devices (or through the web interface) sometimes download to this machine, and sometimes don't.

I have investigated the first error message and found this solution, that I should insall the libcanberra-gtk-module. But when trying to install it, it is already installed. Just to be sure, I reinstalled it but it seems to have had no effect.

I attempted to investigate the second error message and found that lots of different programs give similar error messages, but all of the solutions I could find seemed to be specific to the program that was under discussion on that particular thread.

Any thoughts on how I could solve this? Or at least what I can try next?