Bug#589923: debian-installer: Rescue mode fails to determine codename for the release

[bvrom <bvrom@yahoo.com>]

Package: debian-installer
Version: Lenny 5.0.5
Severity: normal

I am going booting into rescue mode from the Lenny minimal install business cd (point release 5.0.5).
After selecting to install grub from the menu the rescue mode takes me to the partitioner (this is normal).
In the partitioner I choose for automatic partitioning, use whole disk and seperate partitions for /home, /var etc.
The program continues normally until I get a red screen saying:
"[!!] Install the base system
Debootstrap Error
Failed to determine codename for the release.
"

In tty4 I see:
....
cat: can't open '/dev/md0/device': Not a directory
base-installer: error: exiting on error base-installer/no_codename

Full syslog is included with this bug report.

I think this happens because the kernel still thinks somehow it has to do something with the sw raid device that was there in the partition table before I started partitioning in rescue mode.
I have seen with other installations sometimes that the installer gets confused when there are raid devices from a previous installation attempt.

I have included fdisk -l with this bug report (generated after I got the error). 
Before partitioning both sda en sdb had the same partition table and there was a software raid md0 using sda2 and sdb2.

I filed this to debian-installer because I expect this to be not specific to rescue mode.