Sean,
  I download the Mason from your webpage and zip it to C:/appl/Mason.
Then I run the mason/start/mason.bat. And add the directory to the
ClassPath.
However, I went to the C:\appl\Mason\mason\sim\app\tutorial1and2
directory. I run the command such as javac CA.java. The system
generates the following error:

C:\appl\Mason\mason\sim\app\tutorial1and2>javac CA.java
CA.java:6: cannot access sim.engine.Steppable
bad class file: C:\appl\Mason\mason\sim\engine\Steppable.class
class file contains wrong class: Mason.sim.engine.Steppable
Please remove or make sure it appears in the correct subdirectory of
the classpa
th.
public class CA implements Steppable
                           ^
1 error

Could you help me to setup my coding environment? I run it in windows
XP.

Thank you
Best Regards
Le Zhang