I have installed ubuntu Lamp stack. But the curl is not enabled, neither can I can find the extension listed in the INI file. I added manually but it didn't work either.
How should I enable Curl then?
From http://buzznol.blogspot.com/2008/12/install-curl-extension-for-php-in.html:
sudo apt-get install php5-curl
After installing libcurl you should restart the web server with one of the following commands,
sudo /etc/init.d/apache2 restart
OR sudo service apache2 restart