Acrobat 5 "upgrade" CD flawed?

There appears to be a problem which only affects the "upgrade" version of the Adobe Acrobat 5 CD (see previous coverage one and two). David Peltz writes:

"I chose to upgrade from Acrobat 4 to Acrobat 5 by purchasing the 'upgrade' CD direct from Adobe. I could not get the installer work. Either the install failed, or, if I managed to get it installed, the program would not create PDF files.

Hours spent on faulty installation attempts and phone conversations with Adobe's Tech Support and Customer Service yielded plenty of suggestions, but no viable solutions. The Adobe on-line Acrobat forum has messages from other users with similar problems. [One message suggests the problem is caused by multiple copies of Acrobat, perhaps different versions, installed on the same system.]

I eventually obtained a 'full' version of Acrobat 5 and, on the very first try, it installed correctly and works fine."

Update: Micah Forbes adds: "It seems the Acrobat 5.0 upgrade behaves the same way the Photoshop 6.0 upgrade does: As you described in this article, it needs to find an installer file."