You may see the above error in a log file while trying to debug issues in Crossover, or in terminal if you're running an application via terminal. This error tends to be harmless as far as Crossover's functions are concerned, but if you'd like to make it go away please follow the instruction appropriate for your version of Ubuntu.
1. Open a terminal
2. Issue the command: sudo apt-get install libp11-kit-gnome-keyring:i386