I installed Steam, I can start it, but after a few seconds it closes without any errors. What can I do to fix?

When starting with a terminal:

mark@Team-Korkel:~$ steam

rm: kan ‘/home/mark/.steam/steam’ niet verwijderen: Is een map

rm: kan ‘/home/mark/.steam/bin’ niet verwijderen: Is een map

Running Steam on ubuntu 14.04 64-bit

STEAM_RUNTIME is enabled automatically

[2014-05-27 15:27:50] Startup - updater built May 20 2014 18:30:56

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Looks like steam didn't shutdown cleanly, scheduling immediate update check

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

[2014-05-27 15:27:50] Checking for update on startup

[2014-05-27 15:27:50] Checking for available updates...

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

[2014-05-27 15:27:51] Download skipped: /client/steam_client_ubuntu12 version 1400690891, installed version 1400690891

[2014-05-27 15:27:51] Nothing to do

[2014-05-27 15:27:51] Verifying installation...

[2014-05-27 15:27:51] Performing checksum verification of executable files

[2014-05-27 15:27:51] Verification complete

Gtk-Message: Failed to load module "overlay-scrollbar"

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

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element

Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element

Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number

[0527/152752:WARNING:proxy_service.cc(958)] PAC support disabled because there is no system implementation

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

[HTTP Remote Control] HTTP server listening on port 41912.

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Generating new string page texture 2: 48x256, total string texture memory is 49,15 KB

Generating new string page texture 3: 256x256, total string texture memory is 311,30 KB

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

local (potentially out of sync) copy of roaming config loaded - 226 bytes.

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Adding licenses for the following package(s): 0

roaming config store loaded successfully - 226 bytes.

migrating temporary roaming config store

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

ExecCommandLine: "/home/mark/.steam/ubuntu12_32/steam"

System startup time: 15,86 seconds

Running Steam on ubuntu 14.04 64-bit

STEAM_RUNTIME has been set by the user to: /home/mark/.steam/ubuntu12_32/steam-runtime

Generating new string page texture 70: 128x256, total string texture memory is 442,37 KB

Generating new string page texture 71: 128x256, total string texture memory is 131,07 KB

Generating new string page texture 72: 64x256, total string texture memory is 507,90 KB

Generating new string page texture 73: 32x256, total string texture memory is 540,67 KB

ExecCommandLine: "/home/mark/.steam/root/ubuntu12_32/steam steam://open/driverhelperready"

ExecSteamURL: "steam://open/driverhelperready"

Installing breakpad exception handler for appid(steam)/version(1400690891_client)

Generating new string page texture 80: 8x256, total string texture memory is 548,86 KB

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

[0527/152809:WARNING:backend_impl.cc(1930)] Destroying invalid entry.

Using 14.04 64 bit system.