Check the compatibility list and see if your is listed. As new cameras come out, some don't make the list in time and have to wait for the next full version of photoshop, which is usually around the time that the next version is on the market.
List for CS6 and Lightroom are at http://www.adobe.com/products/photoshop/extend.html
So if yours is not on the list for your version, you have three choices, you can either upgrade photoshop, get lightroom(assuming it on the list for lightroom) and finially download
DNG Converter is at
I have Canon 5D Mark III, Photoshop CS6, and Lightroom 4.2. Downloded all updates for both and still does not read my raw files
Support for Canon 5D MIII RAW files was announced in ACR 7.1 (Adobe Camera Raw 7.1).
The current stable release is ACR 7.2 while ACR 7.3 is still a Release Candidate (Beta).
Starting ACR 7.2, Adobe stopped supplying a manual download link which was available till 7.1. Adobe Application Manager (AAM) is the only way for you to update to ACR 7.2.
However, here is a direct download link that AAM connects to for the download that you can use to grab the .zip or .dmg (Mac) file. Download and install. See if you're able to open your files then.