I've never used this, so I'm afraid I'm not much help, but I can offer suggestions:
Have you verified that you are using the latest version of this plugin and that it is WP 2.x compatible? (I'm assuming that you use the latest version of WordPress)
Have you gone over the author's installation instructions to ensure that it was setup correctly?
Have you contacted the author directly? (perhaps there's a bug?)
Has it ever worked (that you know of)? If so, do you know around when it stopped working? i.e. when WordPress was upgraded, or a certain other plugin installed...
Are there any error.log files on your server? (you never know, I've found some before and never knew a plugin had a problem until I saw the file)