The best thing you can do now is contact a NJ attorney for assistance. If you want to find an attorney in your area here on AVVO you can select "Find a Lawyer" at the top of the page. Good luck.
I agree with Mr. Meaney, this is obviously very important to you since you took the time and effort to file the initial expungement paperwork yourself, but now you need to consult with an experienced NJ attorney to see if you have any options to challenge the court's denial of your request. There may be short deadlines within which to file such a challenge, so act quickly. Good luck.
No FL lawyer (except perhaps for one who is dually licensed in both FL & NJ) can answer why NJ failed to expunge your file, but, from what you've stated, had the application been submitted in FL, then it would likely have been denied as well.
In FL you can seal or expunge one qualified case unless you have a prior conviction, then you can't seal or expunge anything. It may not be fair but, unfortunately those are the rules.
If you wan tot know why NJ did what it did, whether or not their decision was lawful and or if you have any alternative avenue or recourse available to you, then I suggest that you cut, paste and repost your question but instead of listing your location as NPR, FL that you list your location as __________, NJ.
Get a NJ attorney fast. In Florida, DUI convictions cannot be expunged because there is a mandatory adjudication on your record. But no Florida attorney will be able to help you with the process in NJ. Good luck.