Improved the error diagnosis, after seeing...

Improved the error diagnosis, after seeing http://www.nabble.com/error-installing-hudson-as-a-windows-service-tt21378003.html

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@14315 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/Util.java

@@ -323,6 +323,17 @@ public class Util {
         return null; // no message
     }
 
+    /**
+     * Gets a human readable mesasge for the given Win32 error code.
+     *
+     * @return
+     *      null if no such message is available.
+     */
+    public static String getWin32ErrorMessage(int n) {
+        ResourceBundle rb = ResourceBundle.getBundle("/hudson/win32errors");
+        return rb.getString("error"+n);
+    }
+
     /**
      * Guesses the current host name.
      */

core/src/main/java/hudson/util/jna/JnaException.java

 package hudson.util.jna;
 
+import hudson.Util;
+
 /**
  * Exception in the registry code.
  *
@@ -7,6 +9,6 @@ package hudson.util.jna;
  */
 public class JnaException extends RuntimeException {
     public JnaException(int errorCode) {
-        super("Win32 error: "+errorCode);
+        super("Win32 error: "+errorCode+" - "+Util.getWin32ErrorMessage(errorCode));
     }
 }