Download sites for this version of Acrobat suggested elsewhere by Adobe Community members do not seem to work.
This link to the trial version of Acrobat Pro X works fine. It's the one recommended every time by forum regulars.
http://prodesigntools.com/all-adobe-cs5-direct-download-links.html
You must follow the Very Important Instructions first before clicking the download link, otherwise the link will not work.
Launch the trial then enter your serial number to license it.