Bug#528605: Similar problem here

[Bernat Arlandis i Mañó]

Newly installed kernels don't boot after installing gparted, reason: 
root device not found. I have just one SATA HDD, the SATA driver finds 
the disk and partitions, but /dev just had the drive (sda) and no 
partitions.

I uninstalled gparted and its dependencies:
dmraid
kpartx
dmsetup
gparted
libdmraid1.0.0.rc15
libparted1.8-10

Now, reconfiguring the kernel (making a new initrd image) it boots 
again. From these packages, dmraid, kpartx and dmsetup added udev rules. 
Also, dmraid adds a local-top script.

Any of these packages could be at fault, right now I can't do more 
testing, sorry. I have a nforce4 chipset with a raid controller not 
being used.

Hope this helps.

-- 
Bernat Arlandis i Mañó