Just when I thought I was done troubleshooting MU for the weekend, I ran into a serious issue:
Whenever I go to edit a page, upon saving it MU sends me to the wordpress url where the page should be located and throws up a 404 error. At first I thought my work had simply dissappeared, but then I realized it had saved what should have been a page as a post instead!
If I create a new page and then paste the contents back in then delete the old post then I'm good to go, but I tried this on a test blog and the problem was pronounced there too.
Are there any ideas as to why this might be happenning? The only other major change to my install other than the 1.0 upgrade, was to integrate BBPress (finally!) into my site (sharing users and cookies), but I didn't think that would be a problem.
EDIT: Culprit FOUND!
The issue is the MU Admin Bar Plugin. While editing posts using the "Edit" button is fine, using the same "Edit" link to edit a page will result in the saved page turning into a saved post and the original page being deleted.
I think we need to find a way to either disable the Edit button on Pages or provide the correct url when Blog Authors are on their pages.