[Plugin: WP Ajax Edit Comments] users anonymous cannot add comments ???

Why in my website users cannot add comments, this errors was showing after when I install plugin WP Ajax Edit Comments. Wend somebody click submit comment it show a error : You sending comments too fast bla bla bla… and it is always showing. Thx for reply.

http://ww.wp.xz.cn/extend/plugins/wp-ajax-edit-comments/