We have been getting reports that some developer had trouble installing the Java ME SDK 8 EA plugins into NetBeans. We are working on fixing the issue, in the meantime please try the workaround posted in the Java ME SDK forum:
Java ME SDK 8.0 EA Netbeans plugin installation problem
Also be sure to check the latest ME SDK 8 EA Release Notes for late-braking information:
Sorry for the inconvenience.