unable to install Adobe 3.0 on mac el capitan 10.11.6

i downloaded the program and open the installer.  A box opens saying it is trying to verify the installer. it stops there and will not go any further. This whole problem started trying to download a library book onto my nook. When trying to move the downloaded book to ADE got an error code 2038. After researching, it was suggested to uninstall ADE and download either version 2.0 or 3.0.  i uninstalled the older version of ADE i was running and now i'm having this verification problem.