I have same problem. I do successful registration for Java, but unsuccessful for NetBeans.
I tried to request new password few times, no luck.
Few years ago I created separated accounts for Java and NetBeans. Today Oracle forwards me to one common registration page. Probably the problem relates to this difference.
Same problem here. I installed NetBeans IDE 6.9.1 and Java SE in one download bundle. I receive the message "invalid registration data" while registering Netbeans. Does somebody know what the problem/solution is?