That error occurs when a handle hasn't been defined for the cURL functions.
There should be a statement such as
PHP Code:
$my_variable = curl_init('www.website_to_download_from.com');
Which sets the handle (contained within $my_variable in this example) that the cURL functions will use to identify the resource to be used.
For some reason, the handle isn't being defined. It is possibly occurring because the URL for the XML feed hasn't been defined somewhere in the script's configuration.
I suggest you double check the configuration for the plug-in, in particular where you define the URL for the XML feed.