Like many of you, I spent a whole day trying to resolve the wrong version or
corrupted MAPI32.DLL error. I tried all suggestion I found in the discussion
group. Nothing worked. That included delete the MAPI folder, rename the
MAPI32.dll file in System32 folder. I even removed the Window Desktop
Search. Outlook still gave me the error message.

Then, the light came on. I realize I have been using the Outlook shortcut
in Start Menu and the one I copied to the Quick Launch. Office 2007 Beta
place the Outlook.exe file in a different folder than Office 2003. (Program
Files\Microsoft Office\Outlook 12). Once I corrected the links, everything
works. The MAPI32.DLL error message is gone.

Before you start pull teeth and uninstalling the beta, check your shortcut.