Please ensure that you have Adobe Flash Player installed on your computer before using these CD-ROMs. You can obtain the install program from the Adobe website (www.adobe.com).
Depending on your system configuration, you may see the following message when you start the CD-ROM:

Selecting Aceptar (twice if the message is repeated) should enable the CD-ROM to run normally.
If you wish to stop this warning appearing, you will need to modify the security settings for Flash in your browser (this requires an Internet connection). To do this, open your browser and go to the configuration page at the following URL:
www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager04.html
(you may be directed automatically to this page if you select Configuration in the message screen above, but in some cases this option will not work).
This will take you to the Global Security Settings Panel (the language in which this appears depends on your operating system):

Here, simply select the option Always allow (Permitir siempre):

This completes the configuration process.
If you prefer not to apply global Flash security settings to all files, it is possible to specify specific files or folders that should always be trusted. To do this, use the Always trust files in these locations (Confiar siempre en los archivos de estas carpetas y archivos) option at the bottom of the same control panel. Click on Edit (Editar), then Add (Agregar), locate the folders or files and confirm the selection:

If you still have problems opening the CD-ROM, open the file bugs_cdx.htm (where x is the corresponding Bugs level number) in the \files directory on the CD-ROM instead of comienzo.htm.