I used the predecessor to the footer plugin earlier, called headerfooter. I remember it sometimes working, sometimes not. Definitely it was not simply a caching issue. I gave up on the plugin then, but added a footer page via DW's inbuilt template functionality, which is a simple addition to your theme's main.php (usually):
<?php tpl_include_page('pagefooter', true, true)?>
Which will take the page "pagefooter" from current or parent namespace and display. Not sure if it will be able to use the @NS@ syntax and such, but I'd be interested to hear how you solve your dilemma. 🙂