Error during Base groupinstall

Hello,

I got the following error when I was trying to
setup a xen CentOS guest on a Ubuntu host. I was
trying: yum --installroot=/xen -y groupinstall Base
and I got the error:
==================================================
(373/375): openldap-2.3.2 100%
|=========================| 294 kB    00:05     
(374/375): dhcdbd-2.2-1.e 100%
|=========================|  61 kB    00:00     
(375/375): python-2.4.3-2 100%
|=========================| 5.9 MB    00:12     
warning: rpmts_HdrFromFdno: Header V3 DSA signature:
NOKEY, key ID e8562897
Importing GPG key 0xE8562897 "CentOS-5 Key (CentOS 5
Official Signing Key) <[email protected]>" from
http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-5
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 236, in
user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 188, in
main
    base.doTransaction()
  File "/usr/share/yum-cli/cli.py", line 364, in
doTransaction
    if self.gpgsigcheck(downloadpkgs) != 0:
  File "/usr/share/yum-cli/cli.py", line 464, in
gpgsigcheck
    self.getKeyForPackage(po, lambda x, y, z:
self.userconfirm())
  File
"/var/lib/python-support/python2.5/yum/__init__.py",
line 2571, in getKeyForPackage
    misc.import_key_to_pubring(rawkey,
po.repo.cachedir)
  File
"/var/lib/python-support/python2.5/yum/misc.py", line
278, in import_key_to_pubring
    ctx = gpgme.Context()
NameError: global name 'gpgme' is not defined
====================================================
I am using version 3.2.12-1.1.

Any suggestions on what could be causing the above.
Is it possible to start from where it left off
(ie it already downloaded the required packages)?

Thanks