User applications randomly segfault

User applications, specially more complex ones, segfault randomly. Firefox segfaults 5 to 10 minutes after opening (usually when i try to open a new tab), yakuake crashes at random times, a few proprietary applications crash (sametime, Lotus Notes). I have this computer which is a Thinkpad T400, but my other computer that is at the same linux version (3.0.0-18, although 64 bits) does not crash.

It seems to affect more user applications than root applications. As an example, apport-bug failed every single time when running it as an user:

[patola@ubuntola patola]% apport-bug linux-image-3.0.0-18-generic
Segmentation fault
[patola@ubuntola patola]% apport-bug linux-image-3.0.0-18-generic
Segmentation fault
[patola@ubuntola patola]% apport-bug linux-image-3.0.0-18-generic
Segmentation fault
[patola@ubuntola patola]% apport-bug linux-image-3.0.0-18-generic
Segmentation fault
[patola@ubuntola patola]% apport-bug linux-image-3.0.0-18-generic
Segmentation fault

But When I ran it as root, it worked
There are some segfaults in /var/log/kern.log:
Apr 4 06:21:58 ubuntola kernel: [ 1307.632123] bamfdaemon[8102]: segfault at 8 ip 00c9854c sp bfb893c0 error 4 in libstartup-notification-1.so.0.0.0[c96000+8000]
Apr 4 06:31:43 ubuntola kernel: [ 1893.066529] sametime[21341]: segfault at 0 ip 00f02f5d sp 9fdfba20 error 6 in libj9prt24.so[ef7000+26000]
Apr 4 06:35:35 ubuntola kernel: [ 2125.093069] sametime[22101]: segfault at 0 ip 00187f5d sp bfcb6590 error 6 in libj9prt24.so[17c000+26000]
Apr 4 06:37:05 ubuntola kernel: [ 2214.797569] sametime[23525]: segfault at 0 ip 0019ff5d sp a34f4aa0 error 6 in libj9prt24.so[194000+26000]
Apr 4 10:14:41 ubuntola kernel: [15270.591042] notes2[9295]: segfault at 0 ip b72e7f52 sp 9bdadbf0 error 6 in libj9prt24.so[b72dc000+2a000]

When I revert back to an earlier kernel, everything works perfectly. A colleague of mine that also uses a Thinkpad also suffered this bug.

Ubuntu 3.0.0-18.31-generic 3.0.26

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: linux-image-3.0.0-18-generic 3.0.0-18.31
ProcVersionSignature: Ubuntu 3.0.0-18.31-generic 3.0.26
Uname: Linux 3.0.0-18-generic i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu4
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: patola 2853 F.... pulseaudio
CRDA: Error: [Errno 2] Arquivo ou diretório não encontrado
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfc020000 irq 48'
   Mixer name : 'Conexant CX20561 (Hermosa)'
   Components : 'HDA:14f15051,17aa211c,00100000'
   Controls : 16
   Simple ctrls : 8
Card29.Amixer.info:
 Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30, fw 7VHT12WW-1.01'
   Mixer name : 'ThinkPad EC 7VHT12WW-1.01'
   Components : ''
   Controls : 1
   Simple ctrls : 1
Card29.Amixer.values:
 Simple mixer control 'Console',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Thu Apr 5 13:09:43 2012
HibernationDevice: RESUME=UUID=55211457-f1e8-4f23-952b-ff83b48dacdb
MachineType: LENOVO 6474D54
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcEnviron:
 LANGUAGE=pt_BR:pt:en
 PATH=(custom, no user)
 LANG=pt_BR.UTF-8
 SHELL=/bin/zsh
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-18-generic root=/dev/mapper/rootvg-rootlv ro crashkernel=384M-2G:64M,2G-:128M quiet splash vt.handoff=7
PulseSinks: Error: command ['pacmd', 'list-sinks'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
PulseSources: Error: command ['pacmd', 'list-sources'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-3.0.0-18-generic N/A
 linux-backports-modules-3.0.0-18-generic N/A
 linux-firmware 1.60.1
SourcePackage: linux
StagingDrivers: mei
UpgradeStatus: Upgraded to oneiric on 2012-04-04 (0 days ago)
dmi.bios.date: 04/22/2009
dmi.bios.vendor: LENOVO
dmi.bios.version: 7UET66WW (2.16 )
dmi.board.name: 6474D54
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr7UET66WW(2.16):bd04/22/2009:svnLENOVO:pn6474D54:pvrThinkPadT400:rvnLENOVO:rn6474D54:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 6474D54
dmi.product.version: ThinkPad T400
dmi.sys.vendor: LENOVO