i don't need help cause i solved my problem, but could you fix https url in your plugin ?
My website need to be accessed both in http and in https.
But when i access on https, i received errors on IE. It's due that colorbox script is always loaded with http.
The solution is to replace line 41 in lightboxplus.php file :
$g_lightbox_plus_url = WP_PLUGIN_URL.'/lightbox-plus';
$g_lightbox_plus_url = plugins_url('/lightbox-plus');
See more at http://codex.wordpress.org/Determining_Plugin_and_Content_Directories#Available_Functions
With this, WordPress can manage SSL easily.
Thanks to fix it for the next version :)