Description of problem:
Tried installing a new guest machine in XEN Virtual Machine Manager by NFS
mounting a CDROM drive and then loading the drive with FC6 installation media.
Mount was as follows:
# mount 192.168.2.101:/media/cdrom-hdb /media/nfscdrom-hdb
# mount | grep nfs
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
nfsd on /proc/fs/nfsd type nfsd (rw)
192.168.2.101:/media/cdrom-hdb on /media/nfscdrom-hdb type nfs
(rw,addr=192.168.2.101)

ls /media/nfscdrom-hdb
eula.txt              RELEASE-NOTES-en_US.html   RPM-GPG-KEY-fedora-rawhide
Fedora                repodata                   RPM-GPG-KEY-fedora-test
fedora.css            RPM-GPG-KEY                RPM-GPG-KEY-rawhide
GPL                   RPM-GPG-KEY-beta           stylesheet-images
images                RPM-GPG-KEY-fedora         TRANS.TBL
isolinux              RPM-GPG-KEY-fedora-extras
README-Accessibility  RPM-GPG-KEY-fedora-legacy

In Virtual Machine Manager I gave the installation source as:
/media/nfscdrom-hdb

and at Finish received:
Invalid PV media address
Install location must be an NFS, HTTP, or FTP install source.

Version-Release number of selected component (if applicable):


How reproducible:
always

Steps to Reproduce:
1. described above
2.
3.
  
Actual results:
received error

Expected results:
installs from NFS-mounted media

Additional info: