Hi zemaphore,
welcome to Questions & Answers..
I had a issue installing the updated reader software & this worked for me..
First disconnect your Reader for your PC..
Goto Control Panel & launch Device Manager
In Device Manager click on the Processes tab
Locate & select Reader Apphelper.exe in the list & click end task
then do the same for Reader AppHelper.exe..
Hopefully after ending those processes the reader software should install..