When opening Outlook 2003, you might have the error “MAPI32.DLL is corrupt or the wrong version“. This can be if you had a newer version of Microsoft Office, un-installed it and installed Microsoft Office 2003. This can be fixed by renaming the MAPI file on your computer as above:

Goto C:\Program Files\Common Files\System\Msmapi\1033
Rename Msmapi32.dll to Msmapi32_old.dll
Open Outlook