I cannot read Nikon D600 raw files with CS5, I have tried Camera Raw 6.1 update but that has not worked.
Support was added in ACR 7.3, which is only compatible with Photoshop CS6. You will either need to upgrade to the newer version of Photoshop, or else use the latest DNG converter. The DNG files contain all the raw image data.
Nikon D 600 will work with ACR 7.3 which needs minimum of PS CS 6 : http://helpx.adobe.com/creative-suite/kb/camera-raw-plug-supported-cameras.html
With PS CS 5, ACR 7.3 will not work.
So either you need to upgrade to CS 6 or use DNG converter to convert images to DNG format which you can open in CS 5