With the upgrade to version 3.0.1 of WordPress, then with later updates of plugins, the redirection plugin went haywire.
First, all the redirects broke. I looked in the redirect dashboard and found that all my page redirects now had a trailing slash, which, because I’m using custom permalinks (/%postname%) sends apache to find a directory, not a file.
So I fixed them.
Later I created a new page and the front page was redirected to the new page. In the dashboard under groups => Modified Posts I found a listing for root (/) that was not re-directed anywhere. I deleted it and fixed that error. For a while.
I created a new page, and the redirect for root was back, along with the redirect error.
Here’s the solution I found:
In the Redirection dashboard, under groups, I found the edit group button for the Modified Posts group.
I disabled the redirects for Modified Posts entirely.
I don’t understand the need for this group and wasn’t using that feature anyway. Seems to be working so far.