766.990932] WARNING: at /build/buildd/linux-2.6.38/fs/buffer.c:1151 mark_buffer_dirty 0x75/0x90()

update 28th april 2011:
this bug seemed fixed... With the last updates I haven't got this error anymore for about two weeks!

I get a window that says that Ubuntu encountered a serious problem with the kernel...

ProblemType: KernelOops
DistroRelease: Ubuntu 11.04
Package: linux-image-2.6.38-8-generic-pae 2.6.38-8.42
Regression: Yes
Reproducible: No
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic-pae 2.6.38.2
Uname: Linux 2.6.38-8-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Annotation: Your system might become unstable now and might need to be restarted.
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: SB [HDA ATI SB], device 0: ALC888 Analog [ALC888 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: zenodotus 1463 F.... pulseaudio
CRDA: Error: [Errno 2] Bestand of map bestaat niet
Card0.Amixer.info:
 Card hw:0 'SB'/'HDA ATI SB at 0xf0400000 irq 16'
   Mixer name : 'Realtek ALC888'
   Components : 'HDA:10ec0888,10250202,00100202 HDA:11c11040,10250100,00100200'
   Controls : 22
   Simple ctrls : 12
Card1.Amixer.info:
 Card hw:1 'HDMI'/'HDA ATI HDMI at 0xafbec000 irq 44'
   Mixer name : 'ATI R6xx HDMI'
   Components : 'HDA:1002aa01,00aa0100,00100100'
   Controls : 4
   Simple ctrls : 1
Card1.Amixer.values:
 Simple mixer control 'IEC958',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Mon Apr 18 11:20:32 2011
Failure: oops
Frequency: Once a day.
HibernationDevice: RESUME=UUID=ce846784-f554-4898-aee8-1cd4eac891d3
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110413)
MachineType: Acer Aspire 7535
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-2.6.38-8-generic-pae root=UUID=75c1a1e3-c192-47b7-9a1d-b5789131fd65 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic-pae N/A
 linux-backports-modules-2.6.38-8-generic-pae N/A
 linux-firmware 1.50
SourcePackage: linux
Title: 766.990932] WARNING: at /build/buildd/linux-2.6.38/fs/buffer.c:1151 mark_buffer_dirty+0x75/0x90()
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/22/2009
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: V1.07
dmi.board.name: JM70PU
dmi.board.vendor: Acer
dmi.board.version: Rev
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrV1.07:bd06/22/2009:svnAcer:pnAspire7535:pvr0100:rvnAcer:rnJM70PU:rvrRev:cvnAcer:ct10:cvrN/A:
dmi.product.name: Aspire 7535
dmi.product.version: 0100
dmi.sys.vendor: Acer