CS2 will not install or run on OS X Yosemite. CS2 is far too old.
There is no way around that.
Eileen - I also had issues with Photoshop and Dreamweaver after I installed Yosemite. I went to the link below and download a the new Java. It solved the problem for me. BUT, I have CS5........so I don't if it'll work for you.