I am seeing an issue when I attempt to upgrade my older windows host DP clients from 9.07 to 9.08. Newer windows (2012, etc.) upgrade just fine. Windows installation server is on version 2012 with DP 9.08. The cell manager is RHEL 6 w/9.08. Here is what I get on older windows hosts when I try to upgrade them to 9.08 from 9.07, seems to be all older win2003, and win2008. I've been running on 9.07 for months now without issue. I am currently just continuing to have those older windows servers use the 9.07 DA and that is working fine. I believe the issue may be that the root CA cert required is not available to these older hosts via the autoupdate of same. All my hosts can reach the internet fine (i.e. not disconnected) and I see evidence of them successfully reaching to get updated root CA certs at upgrade time. The Comodo cert is not present on the old hosts, but is present on the hosts that can be successfully upgraded. I am not sure how to load the cert onto the old hosts and whether that is a red herring or the solution or cause of the problem.
[Critical] <HOSTNAME> [70:32] Digital Signature verification of the install kit failed.
[Critical] <HOSTNAME> Cannot start setup process from the Data Protector share on
your Installation Server, system error:
 The parameter is incorrect.
(System error should give description of the problem.)
* Make sure that Data Protector share on your Installation Server is visible on the network
(in MS-DOS prompt on client type: dir \\<IS_COMPUTER_NAME>\OmniBack)
* Make sure that Data Protector Inet process is not running under a user account, which does
not have access to the Data Protector share on the Installation Server computer
(usually this is local account)