You'll need to include much more information to get a useful answer here: which camera; raw files (assume so, but could be JPEG, TIFF); version of ACR (4.something); computer (Windows, Mac), etc.
Here's a wild guess though - you're using a new (or newish) camera with this older version of PS which (assuming you are trying to open raw files) doesn't support the camera in question. See this FAQ: http://blogs.adobe.com/crawlspace/2011/03/why-doesnt-my-version-of-photoshop-or-lightroom- support-my-camera.html
Hope this helps, but as I say, more information will allow folk on this forum to give you a more definitive answer.
And for reference, there is/was no such product as ''PS3''.
There was PS 3.0 (ancient history), and there was PS CS3 (history).
Details matter. Please provide specific information about what kinds of files you have, etc. I suspect Molly is right on target.
? Afraid your post makes no sense to me. Also, as Noel says, PS3 is ancient history (1994!) - and furthermore, it had no native support for raw files (that wasn't until the first CS version back in 2003).