It looks like you might not have CURL. Check the php.ini file and make sure this line is present
extension=php_curl.dll
Make sure there is no semicolon in front of it. Then restart apache
EDIT
Create a new file and put it in your webroot. Put the following command in this file and load it
<?php
phpinfo();
All modules downloaded for your installation will be shown here. Find the section curl. If it does not appear, you are editing the wrong one php.ini.
The path php.iniis indicated at the top. Open it and do the necessary.