Java Version Problem

I'm running Windows 8

Info: Hi, I'm currently using Java 6 update 41. I'm only able to run Runescape or any other Java client when running on Java 6 for some reason. If I update to the latest java version (7 update 21). An error: (client.class missing) appears on the corner of the window when I try to play runescape. However, OSBot is not able to connect to servers when running java 7. 

So I'm stuck using Java 6, since it's the only that will let me run any java applications.

Problem: I've correctly set up OSBot and it's scripts, but scripts will never be found. Other thing is that every time I open OSBot I have to log in, and re-add my account. 

I used my friends computer to try, he is running Java 7 update 17, and his account is saved even after closing OSBot and re-opening. 

I tried using Java 7 update 17, but it won't let me use RSBot or any other java client, not even go into normal Runescape because of the same message: (Client.class not found). 

If anybody knows what is happening in my computer and how to solve it, help would be very appreciated. 

Thanks to everybody in advance.