Use of undefined constant
<p>I get this error when running a source code downloaded from Internet. How to fix it? It seems to be the PHP version problem. I use PHP 5.3.</p>

<pre><code>[Wed Sep 05 20:31:40 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_RETURNTRANSFER - assumed 'CURLOPT_RETURNTRANSFER' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 209
[Wed Sep 05 20:31:40 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_CONNECTTIMEOUT - assumed 'CURLOPT_CONNECTTIMEOUT' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 210
[Wed Sep 05 20:31:40 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_TIMEOUT - assumed 'CURLOPT_TIMEOUT' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 211
[Wed Sep 05 20:31:40 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_FAILONERROR - assumed 'CURLOPT_FAILONERROR' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 212
[Wed Sep 05 20:31:40 2012] [error] [client 127.0.0.1] PHP Fatal error:  Call to undefined function curl_init() in /home/hieugioi/Workspace/PHP/Couponic/framework/uniprogy/extensions/curl/CURL.php on line 22
[Wed Sep 05 20:33:15 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_RETURNTRANSFER - assumed 'CURLOPT_RETURNTRANSFER' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 209
[Wed Sep 05 20:33:15 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_CONNECTTIMEOUT - assumed 'CURLOPT_CONNECTTIMEOUT' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 210
[Wed Sep 05 20:33:15 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_TIMEOUT - assumed 'CURLOPT_TIMEOUT' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 211
[Wed Sep 05 20:33:15 2012] [error] [client 127.0.0.1] PHP Notice:  Use of undefined constant CURLOPT_FAILONERROR - assumed 'CURLOPT_FAILONERROR' in /home/hieugioi/Workspace/PHP/Couponic/protected/modules/location/worklets/WLocationHelper.php on line 212
[Wed Sep 05 20:33:15 2012] [error] [client 127.0.0.1] PHP Fatal error:  Call to undefined function curl_init() in /home/hieugioi/Workspace/PHP/Couponic/framework/uniprogy/extensions/curl/CURL.php on line 22
</code></pre>
