Error 16!

Trying to deploy Acrobat DC Pro to 75 Windows 7 Pro 32-bit workstations.  Installation goes fine, but users are getting Error 16 messages saying to uninstall/reinstall.  I can run as administrator and fix it, but the problem comes back.  I thought I had traced it to the EULA, found 2 registry changes that were made after I ran as admin.  Still having issues with Error 16.  Seems to be a known issue, but that really doesn't help me unless there's a known fix?

We're a federal government facility, so I am limited as to what I can do in terms of granting users elevated privileges or modifying UAC in Windows.  We have been using Adobe Acrobat X Professional for a few years and have no problems with that.

If there is no fix, is Adobe similar to Microsoft in that if I own 75 Acrobat DC Pro licenses can I legally downgrade to Adobe Acrobat XI?  Assuming there's a fix for XI?