Kernel Panic when removing an USB disk using "Safely Remove" in the Dash

I am having recurrent kernel panics when removing my USB external hard disk (a Samsung Portable G2). When I select "Safely remove" (I have a Spanish version of Ubuntu installed, so the English name may not be accurate), often result in a Kernel Panic. Sometimes the panic happens immediately, sometimes when the device is physically unplugged, and sometimes nothing happens. The error, however, is frequent and quite repeatable.

Following the kernel bug guidelines, I attach the outputs of "cat /proc/version_signature" and "sudo lspci -vnvn"

Please let me know if there is some more debugging to be done to help solve this problem
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ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: linux-image-3.0.0-12-generic 3.0.0-12.19
ProcVersionSignature: Ubuntu 3.0.0-12.19-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu2
Architecture: amd64
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: nicolas 10312 F.... pulseaudio
CRDA: Error: [Errno 2] No existe el archivo o el directorio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0500000 irq 48'
   Mixer name : 'Conexant CX20561 (Hermosa)'
   Components : 'HDA:14f15051,1179ff51,00100000'
   Controls : 14
   Simple ctrls : 7
Date: Thu Oct 6 22:26:39 2011
HibernationDevice: RESUME=UUID=4d523191-815e-4e59-b419-0d0150da2942
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110921.2)
MachineType: TOSHIBA Satellite M305
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-12-generic root=UUID=c63cb018-68a1-48d0-a75e-006b7772ba8f ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.0.0-12-generic N/A
 linux-backports-modules-3.0.0-12-generic N/A
 linux-firmware 1.60
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: Upgraded to oneiric on 2011-10-05 (1 days ago)
dmi.bios.date: 04/10/2009
dmi.bios.vendor: TOSHIBA
dmi.bios.version: V4.00
dmi.board.name: Satellite M305
dmi.board.vendor: TOSHIBA
dmi.board.version: Not Applicable
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: TOSHIBA
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnTOSHIBA:bvrV4.00:bd04/10/2009:svnTOSHIBA:pnSatelliteM305:pvrPSMD0U-01Y00Q:rvnTOSHIBA:rnSatelliteM305:rvrNotApplicable:cvnTOSHIBA:ct10:cvrN/A:
dmi.product.name: Satellite M305
dmi.product.version: PSMD0U-01Y00Q
dmi.sys.vendor: TOSHIBA