Hi suntong!

First of all: please leave assigning the bug priority to the according 
developer. I don't consider it an urgent bug because it neither destroys any 
data, isn't a security issue either nor prevents your system from booting. ;)

Regarding your sound issue: alsa works fine on your box when using the official 
Debian lenny kernel and the same userland? Did you try it on real hardware as 
well (so it's not just a vmware issue)?

Regarding aufs: aufs-modules-2.6.26-grml and aufs-modules-2.6.28-grml are known 
to work just fine, any special needs for an upgrade?

thanks && regards,
-mika-