I have Photoshop CS3 Extended and I have been trying installed plug-in Camera Raw 4.0 or 4.6 in photoshop, but it doesn't work. I have files .cr2. I am sure extension is correct and it wasn't change. I tried install Edit/Preferences/Plug-ins and Library/Application Support/Adobe/Plug-Ins/CS3/File Formats and copy Camera Raw.8bi file inside and when I tried open a .cr2 file, there is a communication "Could not complete your request because it is not the right kind of document". What's the matter? I have windows 7, intel core i3.
Camera raw support is camera model specific. You have a camera model released sometime after ACR version 4.6.
You need to convert your CR2 files to DNG, using the free DNG converter. These can be opened by any ACR version (with the right compatibility setting in the DNG converter).
Yes, I have Canon 5D Mark II. Now it works. Thank you!