This week's book giveaway is in the Java in General forum. We're giving away four copies of Think Java: How to Think Like a Computer Scientist and have Allen B. Downey & Chris Mayfield on-line! See this thread for details.
If you want all your radio buttons to be part of the same group their names must all be the same. So you shouldn't be indexing them like you are. I'm not sure why you think you need to do that but just remove the  indexes from the names.