Sorry Roger - I'm not an Adobe user or fan but I believe that the latest version of ACR will not work with CS2. Older versions of ACR will, but they don't read RAW files from the more recent cameras.
When I berated Adobe for this in another thread I was flamed (or at least gently barbecued) by those who didn't see why Adobe should continue to support a discontinued version of Photoshop. They thought it was perfectly reasonable to pay Adobe another £150 (or whatever) so you could read RAW files from your new camera.
I'm just glad that other software companies have a different attitude towards long-term support.