Virtualbox error after update kernel to 3.0.0-21-generic

After updating from kernel 3.0.0-20-generic to 3.0.0-21-generic, Virutalbox was unable to start the installed Win XP virtual machine, reporting a problem with missing kernel drivers ("Kernel driver not installed (rc=-1908)"). After downgrading to kernel version 20 it works fine. Check all the steps I went through here (https://answers.launchpad.net/ubuntu/+question/201004), as other issues were involved too. I'm reporting this as a bug after the advice given by another user in the Ubuntu Questions thread linked above.

Ubuntu release: 11.10 (oneiric), Linux Kernel 3.0.0-21-generic, GNOME 3.2.1

Package version: virtualbox-qt 4.1.2-dfsg-1ubuntu1

Final note: Virtualbox and the installed Win XP virtual machine had been installed previous to the kernel update and had been working fine for months.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: linux-image-3.0.0-21-generic 3.0.0-21.35
ProcVersionSignature: Ubuntu 3.0.0-21.35-generic 3.0.32
Uname: Linux 3.0.0-21-generic i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu4
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jo 1847 F.... pulseaudio
CRDA: Error: [Errno 2] El fitxer o directori no existeix
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf6ffc000 irq 47'
   Mixer name : 'SigmaTel STAC9228'
   Components : 'HDA:83847616,10280209,00100201'
   Controls : 27
   Simple ctrls : 18
Date: Mon Jun 25 22:19:27 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
MachineType: Dell Inc. XPS M1330
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-21-generic root=UUID=65a44a5f-c1c4-4bfb-898c-6ea4e4a35d1d ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.0.0-21-generic N/A
 linux-backports-modules-3.0.0-21-generic N/A
 linux-firmware 1.60
SourcePackage: linux
UpgradeStatus: Upgraded to oneiric on 2012-06-12 (13 days ago)
dmi.bios.date: 11/19/2008
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A14
dmi.board.name: 0K984J
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA14:bd11/19/2008:svnDellInc.:pnXPSM1330:pvr:rvnDellInc.:rn0K984J:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: XPS M1330
dmi.sys.vendor: Dell Inc.