dng converter not working..

I have installed the dng converter 8.1 and am ready to rip my hair out!! I have Photoshop CS5 and it won't recognize my new Nikon D7100 raw files, so dng converter it is... NOT! When I initially installed the converter it worked on about 50 files then stopped, with the message "there was an error writing the file". I tried again later several more times with the same result. I deleted the dng converter and reinstalled, same thing. I moved the dng files that it did convert to trash in case there was a problem because of duplicates and it won't convert anything, even the files it had previously worked on.. HELP!