Does anyone else have a problem viewing the Java challenges? In Firefox my browsers keeps closing when tryin to open a page with Java on, and in IE it says something about Micro$oft and will not run it

No problem here. Make sure you have java installed properly. Download what you need from Java.com (for users) and java.sun.com (for developers).

You need JRE 1.5 at least to view them
To get them solved I believe JDK 6 is the perfect choice