Busybox appears when booting UNR 9.04 on EeePC 701

[John McCabe-Dansted]

I cannot boot UNR 9.04 on my EeePC. The following two lines appear over and over again.
[...] EXT3-fs: mounted filesystem with ordered data mode.
[...] kjournald starting. Commit interval 5 seconds

Then I am presented by BusyBox. Shortly after, I get:

[ 190.839295] sd 2:0:0:0: timing out command, waited 180s
[ 190.839420] sd 2:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[ 190.839589] sd 2:0:0:0: [sdb] Sense Key : Hardware Error [current]
[ 190.839795] sd 2:0:0:0: [sdb] Add. Sense: Unrecovered read error
[ 190.839968] end_request: I/O error, dev sdb, sector 1990640
[ 190.840080] Buffer I/O error on device sdb, logical block 248830
[ 370.855316] sd 2:0:0:0: timing out command, waited 180s

Which then repeats every 180s.

There is no sdb in my /dev directory, only sda (And sda1-4). sda is clearly were Xandros is installed.

At first I assumed there was something wrong with my SD card. However, this occurs on both my SanDisk 4.0GB SD Card and my SanDisk 1.0GB SD Card. I occurs whether I use the SD card reader built into the EeePC or an external SD Card reader. I can read/write the card fine on both my EeePC (using the Xandros based default OS) and my Desktop (using Ubuntu 8.10 and 9.04). In fact I can even boot UNR from the USB stick under KVM on my Desktop, using the command
"sudo kvm /dev/sdc" (X does not seem to work under KVM, but I do get a normal text terminal rather than BusyBox so the boot process itself is fine under KVM).