Mmm strange. Could you do me a favor, and download this development build and install it. This gives me more insight in what is happening on your site (it will print some plugin related stuff into the html source as comments, no private or other plugin related stuff).
You can install it by removing the old one, and install this one (and activate) you won’t lose any data. Or replace the content of wp-content/plugins/attention-bar with the content of the zip file.
https://pascal.dreissen.nl/wp-content/uploads/2011/06/attention-bar.zip
Give me a reply when you have done this, thanks!