Notice: This fix is for Windows Sever 2008 R2, but might work on other versions of windows too!

These days I am preparing to teach the new Opalis Course MOC 50507A.

I have installed several Opalis 6.3 Test environments before, and have always had problems installing the Operators Console.

I was really happy when I found the great utility made by Kelverion which I described in this blog article

Unfortunately the console did not work in my environments, even when everything was correctly installed. I tested on 3 environment and I got the same error.

All servers is Windows Server 2008 R2 x64 which is the standard we use for all installations, unless other requirements is stated.

I got this error:


Lets take a closer look:

Exception in thread "main" java.lang.NoClassDefFoundError: Files
Caused by: java.lang.ClassNotFoundException: Files
at Method)
at java.lang.ClassLoader.loadClass(
at sun.misc.Launcher$AppClassLoader.loadClass(
at java.lang.ClassLoader.loadClass(
at java.lang.ClassLoader.loadClassInternal(

I tells us that there is a error in the main section of the program/java server, and it cannot find the Class Definition file for something called “Files”


  1. Download a newer version of Java JDK x86. I used the Java 6 update 26, Get it here
  2. Install on the Server running the Operator Console
  3. Change your “JAVA_HOME” environment variable to the new java installation.
  4. Old location was  called jdk1.6.0_04, change it to jdk1.6.0_26 (or the installation folder of the version you installed).
  5. Restart service, or start run.bat! and you’re done!

P.S. Remember to start run.bat as admin!

I have seen other problems, due to paths in the PATH system environment variable, I have fixed this by changing the run.bat file.

I think this problem was exclusively on one of my setups, but if you have problems, please post comment, and I will make another guide for fixing it.

I hope this article will help others with same problem as me! Please do not hesitate to post comments.