Acrobat Pro (11.0) Refuses to Install

I'm trying to install Acrobat Pro 11.0 on my older Mac running Mac OS 10.11.4.  When the installation is nearly complete, I get the message:  "The installation cannot proceed, because some of the processes are running."

This tells me nothing.

When I go to the forum I'm instructed to go to the installation log but when I follow the directions on the forum, there's no file or folder that looks like what's on the forum.

When I go to Adobe's "Contact Us" part of their web site, the only option is this forum.

Anyone have any suggestions what's going on and how to fix this problem?