Hi @joapreditor,
It’s likely that the web feed plugin wasn’t properly installed. What folder did you upload it into? Also, when installing plugins by uploading them directly to the filesystem, you generally need to register them with OJS before they’ll work; to do this, you can run php tools/upgrade.php upgrade on the command line. (Make sure you back up your database and files before you do this.)
Usually plugins should be installed either by uploading the .tar.gz into the plugin management area of the OJS site, or by using the Plugin Gallery; both of these processes will take care of registering the plugin with the system.
Regards,
Alec Smecher
Public Knowledge Project Team