The issue doesn't occur in rhev-hypervisor-5.7, so this is for rhevh 5.7 to 6.2
regression bug.

Test version:
rhev-hypervisor-6.2-0.6.el6

Test step:
[root@localhost libexec]# cat /etc/redhat-release 
Red Hat Enterprise Virtualization Hypervisor release 6.2 (0.6.el6)
[root@localhost libexec]# ./ovirt-config-boot /mnt
installing the image.
source image not valid.
[root@localhost libexec]# ./ovirt-config-boot /mnt 2>/dev/null
installing the image.
source image not valid.
[root@localhost libexec]# grep log_error ovirt-config-boot
      log_error "cannot upgrade from $current_version to $VERSION."
            log_error "Boot partition not available"
          log_error "Could not create DM links"
          log_error "Root partition not available"
            log_error "root partition not available."
            log_error "$(ls -al /dev/disk/by-label)"
      log_error "unable to determine Root partition"
        log_error "version details copy failed."
        log_error "kernel image copy failed."
            log_error "squashfs image copy failed."
        log_error "boot loader install failed."
            log_error "umount /liveos failed."
[root@localhost libexec]# 

So change bug status to VERIFIED.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2011-1783.html