[Plugin: Multiple Post Thumbnails] Multiple “set as…” after uploading

my problem is:
after uploading an image, at the bottom of the modal box and above the INSERT INTO POST button, the link with the SET AS text, appears three times, i dont know whats wrong.

any help please? i really need it to work properly
thanks!

http://ww.wp.xz.cn/extend/plugins/multiple-post-thumbnails/