Might check to see if you have an older version of Acrobat X installed previously under
Mac HD > Applications > Utilities > Adobe Installers
If you have an uninstaller for Acrobat X try uninstalling it then installing again like you did through Creative Cloud.
Thank you for your reply. I am installing on my Windows 7 PC. I have uninstalled and reinstalled Acrobat X several times. The result is the same each time. There is also no obvious uninstaller for Acrobat 9 Pro that is installed as a part of CS4. I need to leave CS4 on the computer but can dump Acrobat 9 Pro and use Acrobat X Pro.