I’m experiencing this (can’t delete posts or add categories) too, on a brand-new install that I did using Dreamhost’s 1-click installation. It seems like maybe some of the fancy AJAX operations are failing silently. I don’t know how to fix it, but here are some workarounds:
- For categories, the “Category Manager” plugin (available here) will let you edit categories.
- To delete a post, go to the “edit” page for that post, and then click the “Delete” button under the text field.
