Login/out or restart your Mac to ensure the version gets picked up. Otherwise...
Based on the requirements for Mac on their website DW CC requires JRE 1.6 - which means the "run time environment" of Java. Although that's a rather old distribution, go here for help on installing that specific version of the JRE:
http://www.piranhamethod.com/develo...1-6-on-your-mac-os-x-leopard-10-5-8-or-later/
The version you downloaded is the complete Java with the Java Runtime Environment (JRE). The JRE consists of the Java Virtual Machine (JVM), Java platform core classes, and supporting Java platform libraries. The JRE is the runtime portion of Java software, which is all you need to run it in your Web browser. I am not a fan of Dreamweaver for other reasons, but add this to my list. Version 7 should have installed the JRE and DW should have picked up on it. Since not, try the link above noting it's an old version and results are unpredictable. So use at your own risk if you insist on using DW.
If this doesn't help and nobody else here has a solution, it might be time to drop DW and switch over to Rapidweaver. But that's plan B, for sure.