I'm a big fan of Vimoutliner and use it for a variety of tasks. I recently managed to break my installation and thought I would document it here for future reference. Vimoutliner comes with a couple of plugins to support checkboxes next to items (for easy to do lists) and a technique called 'hoisting'. Somehow in one of my frequent updates to my configuration I had lost support for both of these features.
It turns out that there is a small difference between the default configuration for Vimoutliner and the way I set up my Vim environment. By convention extension scripts for Vim are stored in a 'plugin' directory under your Vim home (which is ~/.vim by default) and that is where, amongst others, I had place vo_checkbox.vim and vo_hoist.vim. But for reasons known only to itself I have just discovered that Vimoutliner looks for extension scripts in a directory called 'plugins' (notice the plural). So a quick directory add and a couple of svn move's later and I was back in business.