I have CS4 and just bought a D7000, realised it won't convert the RAW images to DNG. I have downloaded the latest converter but it is not seeing the images on the SD card or from a folder on the laptop. Have downloaded several times.
You need to select the FOLDER rather than trying to select individual files within a folder.
Also, its a good idea to always download the files to your desktop, (not recommended to use cable directly to camera or just have SD card in a card reader)
There are people who have reported recent problems when using the Nikon Transfer function to copy raw files. Apparently that changes the content of the files somehow.