You failed to state what version of elements you have and which version of ACR it is use the D60 requires at least ACR 4.4 and the D7100 ACR 7.4 which is quite new Camera Raw plug-in | Supported cameras Also this is an Photoshop forum there is also am Elements forum
You may need to download the 8.6 DNG converter and create DNG files for your NEF files.