Reinstalling Java sometimes fixes strange problems people are having with the games. The best solution for this is removing all old versions first and then installing the latest version.
Before uninstalling, restart your PC, and don't start any Java and/or Internet Explorer/Firefox/Opera programs.. This will guarantee no Java program is running when trying to uninstall.
Go to the 'Add or Remove Programs' option in your Windows Control Panel (Configuratiescherm->Software for dutch Windows). Remove any occurence of Java (JRE/JDK).
Reboot your PC again. Download the latest Java from www.java.com and install.