I have two wordpress installations on the same domain:
I installed Twitter Tools on both and linked them to different twitter accounts. The /wp site is linked to @changeed and the /blog site is linked to @debbyk.
All settings are identical. All plugins are identical. The only difference in the two blogs is the theme used.
The /wp site will let me post to twitter from the sidebar and lets me submit to twitter from a new blog post. It didn't appear to create a digest post however.
The /blog site updated a digest post but when I submit to twitter from a new blog entry, nothing happens. When I try to tweet from the sidebar I get a "tweet post failed" error.
Between the two of them, all of the features work, but I've wracked my brain double and triple checking settings. They are both set to "read and write" in the twitter authentication settings. I can't find much on this error when I do a search. Any ideas would be appreciated!