Can't Edit Any Published Stories

On my drupal 4.7.x install, I can create stories just fine, but if I go back to revise the story none of the changes I make under the "edit" tab do not get updated.

Here's how to reproduce the bug. It requires a pre-published story.

1. login
2. Click on an already-published story. I've created all of the stories and I'm administrator.
3. Click the "edit" tab.
4. Make some changes to the story.
5. Either submit, or preview (shows changes) then submit.
6. I'm returned to the edit tab with the original story. e.g. all changes are lost. Returning to the home page and refreshing confirms shows no changes.

No errors in the logs.

How can I generate some debugging to figure out where the problem lies?