Ошибка установки Steam 14.04.03 (отсутствуют 32-битные библиотеки)

У меня установлен Steam Launcher (установлен через Центр программного обеспечения), при двойном щелчке по нему запускается следующее: в командном окне выполняется следующее:

Steam needs to install these additional packages: 
libgl1-mesa-dri:i386, libgl1-mesa-glx:i386

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libgl1-mesa-glx:i386 : Depends: libglapi-mesa:i386 (= 10.1.3-0ubuntu0.4)
 unity-control-center : Depends: libcheese-gtk23 (>= 3.4.0) but it is not going to be installed
                        Depends: libcheese7 (>= 3.0.1) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

Press return to continue: 

При нажатии Enter появится следующее диалоговое окно:

You are missing the following 32-bit libraries, and Steam may not run: libGL.so.1 

Что делать?