cURL needs to be enabled in the php.ini file.
Go the xamp install directory, in my case it is:
c:\xampp
and open the php.ini file in the php directory:
c:\xampp\php\php.ini
in a text editor. find the following line:
;extension=php_curl.dll
and change it to:
extension=php_curl.dll
save the php.ini file and restart the php server.