Problem with the Netbeans 6.1 installer ????

I was trying to intall netbeans-6.1-ml-windows.exe on vista and faced some inital problems. After setting them correct there was another blocker in the store for me... 

I was installing that from the command line...

D:\softwares\myeclipse>netbeans-6.1-ml-windows.exe --javahome C:\Java\jdk1.5.0_06

and it showed me "Unsupported Java VM version".

So i need to update my Java. 

My concerns in updatng the java are:

1. So when i update will it intall java 6 on my machine???

2. How to stick to java 5.x and get the latest in Tiger???