According to the JavaDoc 
(http://java.sun.com/j2se/1.4/docs/api/index.html):

"public class UnsatisfiedLinkError
extends LinkageError

Thrown if the Java Virtual Machine cannot find an appropriate native-
language definition of a method declared native."

Since you are trying to use a Windows class, this means that the .dll that 
contains the RegOpenKeyEx native method is not installed on your machine, 
or is not on the path.

> Exception in thread "main" java.lang.UnsatisfiedLinkError: RegOpenKeyEx
> at com.ms.wfc.app.RegistryKey.RegOpenKeyEx(Native Method)