Ben Collins ♦ was making some changes to the comment system and something he did caused the userscript to stop working ([ref. 1](http://chat.meta.stackoverflow.com/transcript/message/1454912#1454912), [ref 2](http://meta.stackoverflow.com/questions/190228/did-se-change-something-that-caused-the-pro-forma-comment-script-to-stop-working#comment589333_190228)). The author of the script, Benjol, is aware of the problem and AFAIK is working on a fix. 

Several ([one](http://meta.askubuntu.com/a/7061/44179), [two](http://stackapps.com/a/4241/14817)) workarounds have been suggested until the issue has been resolved.

Tim Stone [said he might be able to give it a look](http://chat.meta.stackoverflow.com/transcript/message/1456036#1456036) as well.