From the instructions (I have done everything described):
After you have made the changes, start your web browser and connect to the
admin tool. Select "Configuration" and "My Store". There should be a new line
at the bottom of the main area that reads, "Allow Category Descriptions."
No problem here
It should already be set to "true"
It is
Finally, go into "Catalog" and "Categories/Products". Edit a category. You will
notice that instead of a "quick box" appearing to the right of the category,
you now get a full page.
No full page here, just the same functionality as before.
Anyone get this contribution to work?