'getpwnam(): name not found: oem' error in OMAP4 10.10 images

Binary package hint: ubiquity

Found on the OMAP 4 image from http://cdimage.ubuntu.com/ubuntu-netbook/ports/daily-preinstalled/20100916/.
Tested on a Blaze ES 2.0 board

After replacing the MLO and u-boot.bin files on the FAT partition, the system boots well, expands the rootfs partition, and reboots with no problem. However, the Ubiquity installer fails to execute then:

Traceback (most recent call last):
  File "/usr/bin/ubiquity-dm", line 531, in <module>
    dm = DM(vt, display, username)
  File "/usr/bin/ubiquity-dm", line 94, in __init__
    self.uid, self.gid = pwd.getpwnam(self.username)[2:4]
KeyError: 'getpwnam(): name not found: oem'
Traceback (most recent call last):
  File "/usr/bin/ubiquity-dm", line 531, in <module>
    dm = DM(vt, display, username)
  File "/usr/bin/ubiquity-dm", line 94, in __init__
    self.uid, self.gid = pwd.getpwnam(self.username)[2:4]
KeyError: 'getpwnam(): name not found: oem'

Early, it also said:

Checking filesystem before resizing... Done.
sh: X: unknown operand

done
... but this may not be related.

See the attached boot log.

Cheers,

Michael.