Alright Deko,

I'm in the process of making a new release, but here's a quick fix for you. It involves just two line changes.

In includes/templates/template_default/sideboxes/tpl_campaignmonitor_sdebox.php, change line 20 from

Code:
//Set the next line, CURLOPT_NOBODY, to 0 to enable debugging.


to

Code:
//Set the next line, CURLOPT_RETURNTRANSFER, to 0 to enable debugging.


And on line 21, change

Code:
curl_setopt($ch, CURLOPT_NOBODY, 1);


to

Code:
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
That should do it. Let me know if you're having any more problems. Future releases will actually use the curlopt codes to display meaningful information, but I haven't done that yet.