Had tested this on my Mac and Debian machines, but came across a change that might help. I've changed the filenames in the plugin, which may alleviate the issue. This isn't enough of a change to warrant a new version (I don't think), but maybe it'll help? To implement, re-download and install the plugin, or install again from the admin panel in WP.
Btw, if you're using PHP earlier than 5.1.2, this likely won't work, as that's when spl_autoload was added. Like I said, if there's enough demand, I'll change the plugin to be more compatible with earlier versions of PHP, but hopefully that won't be necessary (I really like autoload ;) ).
If you're still having trouble with it, let me know!