Installer error for Dreamweaver CS5

I have downloaded the disk image for Dreamweaver CS5, which I purchased a number of years ago and have been using since. I opened the disk image, right-clicked on Install, opened the Contents folder, opened the MacOS folder, and attempted to open the Install Terminal file. I get a message that says ' "Install" can't be opened. You should eject the disk image.'

How do I get a workable Installer for this program?