Plus Pack 2012 fails to re-install

Acronis True Image Home 2012 and Plus Pack 2012 were installed on this machine (Dell Optiplex 9010 with Windows 7 Pro x64) and worked perfectly. I decided to update to Acronis 2015. I uninstalled 2012 and all components using the clean-up tool, installed 2015, and it worked fine, except that 2015 has removed a whole bunch of features that I liked (access to log files, consolidation, specification of numerous options, the entire user interface, etc, etc...). So I decided to go back to 2012. I uninstalled 2015 and used the new clean-up tool for good measure, and then installed and re-licensed and activated True Image Home 2012, and it works fine. The trouble is with the 2012 Plus Pack (for which I also have a license). After rebooting, I tried installing two versions of the 2012 Plus Pack, 6154 and 7133, and both failed to install at the end of the installation process: "An error occurred while installing Plus Pack for Acronis True Image Home 2012." Issue description: "Installation has failed. The configuration data for this product is corrupt. Contact your support personnel." Clicking on "Knowledge Base" leads to a discontinued URL. Trying to contact Acronis support I am told that this product is no longer supported and I must upgrade to 2015. Hey, thanks a lot, I did that, I paid for it, I don't like it, and I'm just trying to get back to where I was (which I also paid for). When I consult the installation file, I see "MSI (s) (9C:C4) [19:52:24:645]: Unexpected or missing value (name: 'PackageName', value: '') in key 'HKLM\Software\Classes\Installer\Products\1E909737356341C40B1E1DD08B649CB2\SourceList'
MSI (s) (9C:C4) [19:52:24:645]: MainEngineThread is returning 1610."

Can anyone help with this?