Share-this plugin dont work?

i’ve just installed a plugin called ‘share-this’ by http://alexking.org/

i’ve activated it n it showed up on my blog nicely, but the problem is ’email this’ function dont work…

social bookmark web work fine…

i’ve try use that ’email this’ function from other website that use the same plugin, using my email and it works (of cos it works) :p

after that i try something else, i try not to fill out the form completely, it showed up this image

http://img72.imageshack.us/img72/530/untitled1mi3.jpg

but when i try that on my site, that image wont appear, it just refresh back to index page instead, u guys have any clue how this thing could happen?