I am seeing this issue with a Windows 2008 R2 box as well. Same errors...
[Critical]<test> [70:32] Digital Signature verification of the install kit failed.
[Critical]<test> [70:32] Digital Signature verification of the install kit failed.
[Critical]<test> Cannot start setup process from the Data Protector share on
your Installation Server, system error:
[87] The parameter is incorrect.
(System error should give description of the problem.)
In general:
* 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)
[Critical]<test> [110:1026] Lost connection to client test1:
Details unknown.