Crazy Outlook problem

I’m running an HP Pavilion laptop with WinXP and Office 2003. Suddenly, when I go to open my Outlook, I get:

Your personal address book could not be opened. The file is either not
accessible or is not a personal address book. Choose Retry to use your
personal address book, or choose Cancel to not use your personal address
book with this application.

Microsoft says this is a designed feature, something about opening .pab and .pst files for read/write access. I have no idea what’s going on. I even uninstalled and re-installed Office 2003, willing to start all over with my address book, but it still won’t open. Now I’m desperate! I have student papers I have to pull down and grade, my own grad work to send in, and Yahoo’s web-based e-mail program is just too clunky!