Facebook Send Button doesn’t work along with Like or Recommend button as said by developers and there are lot of people already complaining about it. Not sure if the problem is because it has not been rolled out for everybody or there is some problem because of the like itself but as of now if you have implemented Like and Send button together using the Facebook Like Plugin, I will suggest you to turn it off if its not working for you.
As of now it just grays out and nothing happens.
Instead, AJ Batac @ His blog has given an example where he has shown that using only a send button works but not along with Like button. The code which you can use only for send button is as follows :
However this will not come right on side of the Like button but on a new paragraph.
For users who want to implement this on WordPress Blog : Us the code as below. get_permlink($post-ID ) will get short version of your post url i.e. ?p=XXX
<fb:send href=<?php echo urlencode(get_permalink($post->ID));?>></fb:send>
The div id just above the script is required as your Facebook Message Box will open right there. In case you are not logged in, you will be prompted for it.