admin/environment/php extension/xmlrpc

To install the xmlrpc library on Windows

1. Open the php.ini file found in the moodle/apache/bin folder
2. Find the line: ;extension=php_xmlrpc.dll
3. Remove the ; at the beginning of the line
4. Restart apache if necessary

To install the xmlrpc library on Unix

1. You need to recompile PHP from source
2. add --with-xmlrpc to the command line when you run configure