[Plugin: Blog Introduction] doesn't work

Hi, i use wordpress 3.1, atahualpa theme 3.5.3 and my site is http://www.ponzaracconta.it

i followed plugin istructions but doesn’t work. In configuration panel i put “yes” to show intro; then “page”; then “manifest-cat-intro” because my category is manifest; then “Yes” to show heanding; “Yes” to show content; then “everyone”; then “no”; then “no”; and “1” to Intro before nth loop.

Aldo the “Preview” doesn’t work.

Please help.

http://ww.wp.xz.cn/extend/plugins/blog-introduction/