I can't load runescape after I choose a world, and its really frustrating:(

Is it showing a blank screen, or is it giving you an error message with it. I cannot help you with the error message, but I can help you with the blank screen. Just go here, and download macromedia flash player. Then it should work.

If that still won't work just change the Java application. You can find that at the bottom of the detail screen.