Error addons

[Divitix]

Hello. I just discovered that there are extensions for download. I downloaded 2 extensions CRM and Mail, and want to add the plugin.xml not added, I also created manually in the plugins folder, this folder: OpenEstate-Tool-Mail within've put the .jar and off I renamed plugin.xml by OpenEstate-Tool-Mail, restarting the program any plugin installed is not displayed.

im using spanish version

What Happend ?