Author Meta drop down Not showing new users/authors since wp 3.1 upgrad

Since the WP 3.1 upgrade, new authors don’t show up in Post Edit Author Meta scroll-down menu (I promised her that her article would be published on Monday). The pre-upgrade authors are still there (actually, they don’t show up on the main blog anymore but do show up in the sub-blogs) What could be causing this problem? I found the following thread which seems related since I exhibit some of the same symptoms (almost no authors in main author meta and no new authors in sub author metas). Seems like they were on to something with one of the RCs but the thread ended with no resolution:

For whatever its worth, I just added a tester user to a sub-blog, and upgraded the user status from subscriber to author. This tester author existed before WP 3.1 upgrade but was not added to this sub-blog nor made an author before the upgrade. Anyway, the tester user also does not show up in the Author Meta drop down menu. Any ideas?