Cross-posted from https://github.com/thor27/steam-login

The first command is just to ensure there aren't any instances running, the second command attempts to launch Steam in Big Picture Mode from the terminal. (Big Picture Mode works just fine from within Steam on this system).

$ killall steam; killall steam.sh; killall MainThrd;
steam: geen proces gevonden
steam.sh: geen proces gevonden
MainThrd: geen proces gevonden
$ steam -bigpicture
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)

Looks like steam didn't shutdown cleanly, scheduling immediate update check
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
unlinked 0 orphaned pipes
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Gtk-Message: Failed to load module "overlay-scrollbar"
[1226/134037:WARNING:proxy_service.cc(646)] PAC support disabled because
there is no system implementation
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
Installing breakpad exception handler for
appid(steam)/version(1355957371_client)
/home/wietse/Steam/steam.sh: regel 287: 6622 Segmentatiefout
(geheugendump gemaakt) $DEBUGGER "$STEAMROOT/$PLATFORM/$STEAMEXE" "$@"

Processor Information:
Vendor: GenuineIntel
Speed: 2667 Mhz
4 logical processors
3 physical processors
HyperThreading: Supported
FCMOV: Supported
SSE2: Supported
SSE3: Supported
SSSE3: Supported
SSE4a: Unsupported
SSE41: Supported
SSE42: Supported

Network Information:
Network Speed:

Operating System Version:
Ubuntu 12.10 (64 bit)
Kernel Name: Linux
Kernel Version: 3.5.0-21-generic
X Server vendor: The X.Org Foundation
X Server release: 11300000

Video Card:
Driver: ATI Technologies Inc. ATI Mobility Radeon HD 5800 Series

Driver Version:  4.2.11995 Compatibility Profile Context FireGL
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 59 Hz
VendorID:  0x1002
DeviceID:  0x68a0
Number of Monitors:  1
Number of Logical Video Cards:  1
Primary Display Resolution:  1680 x 1050
Desktop Resolution: 1680 x 1050
Primary Display Size: 14,45" x 9,02"  (17,01" diag)
                                        36,7cm x 22,9cm  (43,2cm diag)
Primary VRAM Not Detected

Sound card:
Audio device: IDT 92HD75B3X5

Memory:
RAM: 3811 Mb

Miscellaneous:
UI Language: English
LANG: nl_NL.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 267778 Mb
Largest Free Hard Disk Block: 177432 Mb

Installed software: