Technically when you 'root' your NC, your warranty becomes void and B&N is not responsible for any issues. So, this is not the best place to expect answers on a rooted device. You'll have better luck if you post it in forums such as xda-developers.
You can also Google for information on how to 'restore' your NC to a stock or factory image. There are a number of sites that have the information. If you like you can then leave things as is, or attempt rooting again.