The CS2 suite you are using is prolly a demo version. In demo versions you can not save anything.
For best performance get CS4. That is if you have a proper quadcore and/orlatest generation mac.
Bootlegs: there are a couple of CS4 suites available that f*ck up your system during install. Beware!
Free trial of Photoshop
Re: Free trial of Photoshop
I thought you had a CS4 trial? The link I sent was for a CS4 keygen. How did you end up with CS2? 

Re: Free trial of Photoshop
Ironblood, I guess you entered a CS4 serial into CS2. That does not unlock CS2. You are still working with a demo version! If you want to unlock CS2, you need a CS2 serial.