the curl init function is a PHP function.
make sure the CURL Extension is enabled in the PHP.ini file, look for:
;extension=php_curl.dll
and remove the semi colon:
extension=php_curl.dll
Then restart the web server. also make sure the php_curl.dll exists in the PHP extension folder. Not all PHP Installations will allow the enabling of the CURL library, if this is on your local computer, you may need to upload to the remote server for testing.