there is only a few things that would prompt this type of error.
Simply put, it pops up the mood window, however, nothing shows. This means that you have not entered in the correct code, or have not entered in the code in the member.php file correctly.
Have you created the mood template? Do you have the right address in place, for the mood popup to hook up with the mood window?
Basically, and I do mean this in the best way, re-read the instructions.
Close to 400 downloads, and not one problem mentioned that wasnt user error.