No Image and Receiving Warning Message

Hi,

I have installed the latest version but getting the following error, for 1st post it did imported and created a thumnail but afterward its not importing any image now and i am receiving the following error;

Warning: Cannot modify header information – headers already sent by (output started at /home/cbblogs/public_html/wp-admin/includes/template.php:2020) in /home/cbblogs/public_html/wp-content/plugins/magic-post-thumbnail/magic_post_thumbnail.php on line 442