kernel_thread_helper message in Maverick

[gamx]

Hi,
I have upgraded my desktop to Maverick (from Lucid) and I have problems with the kernel. With the standard kernel (2.6.35.22) the booting process gets stuck with a message "kernel_thread-helper +0X0/0x10". Somehow, it seems to be related to acpi and, in fact, if I turn off acpi in grub the system boots. Still, this is a problem in itself, since now the boot process is text only, etc but I can live with that, I guess.
However, I have encountered a second (and worse) problem. Audio does not work properly and all sounds get interrupted (or alternated with other sounds), as if we were trying to play the same sound twice with half a second of delay. It is difficult to explain... I have no idea whether this is due to the kernel or the acpi option I have used.
The only additional piece of information I have is that, fortunately, the upgrade process left behind one of the old 2.6.32-25 kernels. With that kernel everything works perfectly (including acpi). I guess this means that it cannot be a hardware problem or related to other parts of ubuntu. It must be somehow related to the kernel.
Can you help please? Thanks!

My hardware configuration is the following:

sudo lshw -short
H/W path Device Class Description
================================================== =
system APL00
/0 bus APL00
/0/0 memory 128KiB BIOS
/0/4 processor Pentium(R) Dual-Core CPU E5200 @ 2.50G
/0/4/8 memory 32KiB L1 cache
/0/4/9 memory 1MiB L2 cache
/0/17 memory 4GiB System Memory
/0/17/0 memory 2GiB DIMM DRAM 667 MHz (1.5 ns)
/0/17/1 memory 2GiB DIMM DRAM 667 MHz (1.5 ns)
/0/100 bridge MCP73 Host Bridge
/0/100/0.1 memory RAM memory
/0/100/1 memory RAM memory
/0/100/1.1 memory RAM memory
/0/100/1.2 memory RAM memory
/0/100/1.3 memory RAM memory
/0/100/1.4 memory RAM memory
/0/100/1.5 memory RAM memory
/0/100/1.6 memory RAM memory
/0/100/2 memory RAM memory
/0/100/3 bridge MCP73 LPC Bridge
/0/100/3.1 bus MCP73 SMBus
/0/100/3.2 memory RAM memory
/0/100/3.4 memory RAM memory
/0/100/4 bus GeForce 7100/nForce 630i USB
/0/100/4.1 bus MCP73 [nForce 630i] USB 2.0 Controller (EHCI)
/0/100/8 storage MCP73 IDE
/0/100/9 multimedia MCP73 High Definition Audio
/0/100/a bridge MCP73 PCI Express bridge
/0/100/a/8 bus FW322/323
/0/100/b bridge MCP73 PCI Express bridge
/0/100/b/0 display G98 [GeForce 9300 GE]
/0/100/c bridge MCP73 PCI Express bridge
/0/100/d bridge MCP73 PCI Express bridge
/0/100/e scsi2 storage GeForce 7100/nForce 630i SATA
/0/100/e/0 /dev/sda disk 640GB WDC WD6400AAKS-2
/0/100/e/0/1 /dev/sda1 volume 12GiB Windows NTFS volume
/0/100/e/0/2 /dev/sda2 volume 74GiB Windows NTFS volume
/0/100/e/0/3 /dev/sda3 volume 93GiB EXT4 volume
/0/100/e/0/4 /dev/sda4 volume 416GiB Extended partition
/0/100/e/0/4/5 /dev/sda5 volume 3812MiB Linux swap / Solaris partition
/0/100/e/0/4/6 /dev/sda6 volume 412GiB Linux filesystem partition
/0/100/e/1 /dev/cdrom disk DVD A DH16A6S
/0/100/f eth0 network MCP73 Ethernet
/0/1 scsi6 storage
/0/1/0.0.0 /dev/sdb disk SCSI Disk
/0/1/0.0.1 /dev/sdc disk SCSI Disk
/0/1/0.0.2 /dev/sdd disk SCSI Disk
/0/1/0.0.3 /dev/sde disk SCSI Disk
/0/2 scsi7 storage
/0/2/0.0.0 /dev/sdf disk 32GB SCSI Disk
/0/2/0.0.0/1 /dev/sdf1 volume 29GiB Windows FAT volume
/0/2/0.0.1 /dev/sdg disk 2032MB SCSI Disk