da esse erro aqui o que devo fazer.
Running Steam on ubuntu 15.04 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1431729692)
Installing breakpad exception handler for appid(steam)/version(1431729692)
Installing breakpad exception handler for appid(steam)/version(1431729692)
Installing breakpad exception handler for appid(steam)/version(1431729692)
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
Fontconfig warning: "/etc/fonts/conf.d/70-fonts-bpg-georgian.conf", line 12: bad alias
Fontconfig warning: "/etc/fonts/conf.d/70-fonts-bpg-georgian.conf", line 21: bad alias
Fontconfig warning: "/etc/fonts/conf.d/70-fonts-bpg-georgian.conf", line 30: bad alias
[0521/053916:ERROR:browser_main_loop.cc(170)] Running without the SUID sandbox! See
https://code.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
Steam: An X Error occurred
X Error of failed request: BadRequest (invalid request code or no such operation)
Major opcode of failed request: 154
Serial number of failed request: 40
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request: BadRequest (invalid request code or no such operation)
Major opcode of failed request: 154
Serial number of failed request: 41
xerror_handler: X failed, continuing
Steam: An X Error occurred
X Error of failed request: BadRequest (invalid request code or no such operation)
Major opcode of failed request: 154
Serial number of failed request: 42
xerror_handler: X failed, continuing
glXChooseVisual failedAssert( Assertion Failed: Fatal Error: glXChooseVisual failed ):/home/buildbot/buildslave_steam/steam_rel_client_ubuntu12_linux/build/src/steamUI/Main.cpp:287
Installing breakpad exception handler for appid(steam)/version(1431729692)
Installing breakpad exception handler for appid(steamwebhelper)/version(20150514174016)
Installing breakpad exception handler for appid(steamwebhelper)/version(1431625216)
[0521/053916:ERROR:nss_util.cc(981)] Failed to load NSS libraries.
Installing breakpad exception handler for appid(steamwebhelper)/version(20150514174016)
Installing breakpad exception handler for appid(steamwebhelper)/version(1431729692)
Installing breakpad exception handler for appid(steamwebhelper)/version(1431729692)
assert_20150521053916_6.dmp[4302]: Uploading dump (out-of-process)
/tmp/dumps/assert_20150521053916_6.dmp
assert_20150521053916_6.dmp[4302]: Finished uploading minidump (out-of-process): success = yes
assert_20150521053916_6.dmp[4302]: response: CrashID=bp-86bfb29b-b490-461e-9459-8c10b2150521
assert_20150521053916_6.dmp[4302]: file ''/tmp/dumps/assert_20150521053916_6.dmp'', upload yes: ''CrashID=bp-86bfb29b-b490-461e-9459-8c10b2150521''