Sound doesn't work anymore on EeePC 900 since 10.04 Beta 2

[Chocwise]

Binary package hint: pulseaudio

When running Ubuntu 10.04 Beta 2 from an USB-stick (live system) on my EeePC 900 (no A), the Sound doesn't seem to work. When I play the Free Culture Showcase ogm file, for example, there is no sound. As you can see in the attached screenshot, the slider for the volume is at max. The sliders on alsamixer are at maximum too if that is of interest.
With the Beta 1 it worked fine, since Beta 2 no more.
When I log out of the Gnome session and go to the login prompt of GDM there IS sound though. I can hear the drums there.

I tried muting and de-muting the sound with my Fn+F7 key. Notification shows it has been muted/de-muted but sound doesn't work either way.

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: pulseaudio 1:0.9.22~0.9.21+stable-queue-32-g8478-0ubuntu14
ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
Uname: Linux 2.6.32-19-generic i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC662 rev1 Analog [ALC662 rev1 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC662 rev1 Analog [ALC662 rev1 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/dsp', '/dev/snd/by-path', '/dev/snd/controlC0', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/seq', '/dev/snd/timer', '/dev/sequencer2', '/dev/sequencer'] failed with exit code 1:
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf7eb8000 irq 16'
   Mixer name : 'Realtek ALC662 rev1'
   Components : 'HDA:10ec0662,10438337,00100101'
   Controls : 17
   Simple ctrls : 10
Date: Fri Apr 9 18:22:23 2010
LiveMediaBuild: Ubuntu 10.04 "Lucid Lynx" - Beta i386 (20100406.1)
ProcEnviron:
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: pulseaudio
dmi.bios.date: 05/26/2008
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0601
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 900
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: x.xx
dmi.chassis.asset.tag: 0x00000000
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTek Computer INC.
dmi.chassis.version: x.x
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0601:bd05/26/2008:svnASUSTeKComputerINC.:pn900:pvr0601:rvnASUSTeKComputerINC.:rn900:rvrx.xx:cvnASUSTekComputerINC.:ct10:cvrx.x:
dmi.product.name: 900
dmi.product.version: 0601
dmi.sys.vendor: ASUSTeK Computer INC.