admin/environment/php extension/xmlrpc
From MoodleDocs
To install the xmlrpc library on Windows
- Open the php.ini file found in the moodle/apache/bin folder
- Find the line:
;extension=php_xmlrpc.dll
- Remove the
;
at the beginning of the line - Restart apache if necessary
To install the xmlrpc library on Unix
- You need to recompile PHP from source
- add --with-xmlrpc to the command line when you run configure