The problem with IDEs such as Dreamweaver, is that it is designed for designers. It's a drag-n-drop interface, and doesn't really hold any spectacular services one would actually need when developing a large application such as a game in your case.
You need something that allows you to debug and profile your scripts, and that would allow you to create "hooks" in your application and be able to follow the code execution. I do not know if Dreamweaver has any of this, but I doubt it will do.
NetBeans and Zend are two excellent editors you might want to take a look at.