The problem is that some have issues, some have not. If all have had issues, there is a quite possibilty that I did something wrong. If few people have problems, then I will state the opposite. At this time I only have 3 - 4 people out of 30 people that has problems.
Problems can be everything from Internet connection to not done the procedure correctly. Have you downloaded Java Oracle? http://www.oracle.com/technetwork/java/javase/downloads/index.html
Just follow my guide on everything. Dont let anything out.