Dreamweaver CS5.5 installer issue?

Hi. Can anyone offer a solution to the problem shown in the attached screenshot? (Mac 10.12.2) This is for an older version of Adobe Dreamweaver CS 5.5. (2011) that was deleted. I have the serial number. The download is complete and there is a desktop icon, but this (see screenshot) is as far as I can get. Note that this does not *appear* to be a security issue, since no warning is generated in security preferences regarding the origin of the application. This problem occurred downloading PE 11 but was overridable in security preferences. Command-clicking the "install.app" icon does not work either. Suggestions? –Ric
