I have the 2012.3077 version for all frc related plugins on Netbeans. I'm not quite certain what you mean by the updates URL. In the error message, it at least gave the first half of your URL:
http://first.wpi.edu/FRC/frcjava.html
I looked in the directory of updates.xml in the url you provided, and I found the updates files, but it appears I already have them.