How can I lock, change password and unlock this program?
To change the lock, you will have to log-in with the Administrator, the username that you first set up. If you don't have access to the administrator username and password, then a reinstallation is recommended because there is no way provided to recover the password. I have also checked the online documentation and there was nowhere specified about the password reset.
Download program: http://cybera.sourceforge.net/site/co/project_en.html