Does it work when you update to the 31x.xx series of drivers?

Still fell over. I ran it from terminal and this is the error printed out:

Steam: An X Error occurred
X Error of failed request: BadWindow (invalid Window parameter)
Major opcode of failed request: 40 (X_TranslateCoords)
Resource id in failed request: 0xe00b64
Serial number of failed request: 16695
Generating new string page texture 124: 128x256, total string texture memory is 1.25 MB
Generating new string page texture 125: 256x256, total string texture memory is 393.22 KB
Installing breakpad exception handler for appid(steam)/version(1358447263_client)

It also completed an update whilst it started up.

Hardware print out after update:
Processor Information:
Vendor: GenuineIntel
Speed: 2401 Mhz
4 logical processors
2 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: 3.5.0-22-generic
X Server vendor: The X.Org Foundation
X Server release: 11300000

Video Card:
Driver: NVIDIA Corporation GeForce GT 520MX/PCIe/SSE2

Driver Version:  4.3.0 NVIDIA 310.14
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 59 Hz
VendorID:  0x10de
DeviceID:  0x1051
Number of Monitors:  1
Number of Logical Video Cards:  2
Primary Display Resolution:  1366 x 768
Desktop Resolution: 1366 x 768
Primary Display Size: 13.54" x 7.64"  (15.51" diag)
                                        34.4cm x 19.4cm  (39.4cm diag)
Primary VRAM: 1023 MB

Sound card:
Audio device: Intel CougarPoint HDMI

Memory:
RAM: 3864 Mb

Miscellaneous:
UI Language: English
LANG: en_GB.UTF-8
Microphone: Not set
Total Hard Disk Space Available: 465511 Mb
Largest Free Hard Disk Block: 334635 Mb

Installed software:

Recent Failure Reports:

Just started Steam up again. It crashed again, but didn't print out any errors in the terminal. However, it didn't crash until I clicked on the message notification.

EDIT: Tried again and it only crashed when a friend sent me multiple messages. I 'alt+tab'ed into the window this time.

I've noticed a few people running openbox (LXDE's WM) having some issues. I'm not sure where to start here. I'm sure someone else will pop in with a suggestion.

Just thought I'd give optirun a whirl. Should have tried it before as it seems to be working fine fingers crossed. I assume that primusrun is doing something a bit more complex and is having difficulties with it.

EDIT: I got the BadWindow error again, but this time it hasn't crashed.

EDIT 2: I tried with vblank_mode=0 primusrun and it's not crashing. Seems like it might be how primusrun deals with vblank synchronization.

EDIT 3: Tried playing TF2 with vblank_mode=0, but that crashed. At least with just primusrun, the games work fine.
Error from terminal:
Uploading dump (in-process) [proxy '']
/tmp/dumps/crash_20130120224803_1.dmp
success = yes
response: CrashID=bp-8dec8f2d-90c9-448b-83db-db87a2130120
Game removed: AppID 440 "Team Fortress 2", ProcID 7566
/home/benjamin/.local/share/Steam/SteamApps/[email protected]/Team Fortress 2/hl2.sh: line 72: 7566 Segmentation fault (core dumped) ${GAME_DEBUGGER} "${GAMEROOT}"/${GAMEEXE} "$@"

EDIT 4: I get the same terminal print out with optirun.

EDIT 5: Seems to be the same problem with primusrun on it's own as well. Crash could be caused by the updated driver.

EDIT 6: Downgraded to nvidia-current-updates package from x-swat. vblank_mode=0 primusrun works fine. Primusrun on its own crashes with the below print out:
surface_opengl.cpp (674) : Assertion Failed: texture->m_eTextureFormat == eTextureFormat
Assert( Assertion Failed: texture->m_eTextureFormat == eTextureFormat ):/home/buildbot/buildslave_steam/steam_rel_client_ubuntu12_linux/build/src/vgui2/src/surface_opengl.cpp:674

Installing breakpad exception handler for appid(steam)/version(1358447263_client)
Uploading dump (in-process) [proxy '']
/tmp/dumps/assert_20130120232028_1.dmp
success = yes
response: CrashID=bp-f3df8b97-3d92-451e-b196-17b232130120
ExecCommandLine: "/home/benjamin/.steam/root/ubuntu12_32/steam steam://open/driverhelperready"
ExecSteamURL: "steam://open/driverhelperready"
GLError: 1281
GLError: 1281

Optirun is running Steam fine. So I assume that TF2 was crashing because of the updated driver, but Steam has a problem with the vblank synchronization.

EDIT 7: The below terminal print out appeared after I closed the 'Friends' window. So I think that has nothing to do with the crashing.
Steam: An X Error occurred
X Error of failed request: BadWindow (invalid Window parameter)
Major opcode of failed request: 40 (X_TranslateCoords)
Resource id in failed request: 0x1800bbe
Serial number of failed request: 251320

@gigaSproule Many things have changed over the last year, are you still having trouble?

I use primusrun as part of the advanced commands section, so I haven't seen it happen recently. I forgot to close this issue. Sorry.