MAPI32.DLL error running Outlook 2003

I made the mistake of installing the trial version of Office 2007 on my new
Vista machine. I uninstalled it, and installed Office 2003. Word and Excel
are running great, but I get the MAPI32.DLL error whenever I try to run
Outlook.

I've seen the messages about uninstalling and reinstalling. I've even tried
using the Windows cleanup utility suggested in another thread. I can't
figure out how to delete the three MAPI32.DLL. No go. I can't figure out
permissions, which is my question.

My comment is this. I did delete the other file suggested in a thread, the
MSMAPI32.DLL flie, and I was allowed to delete this one. Once gone, Outlook
started up.