Microsoft Outlook 2000

Hi,
I currently have microsoft outlook 98 installed on a windows nt4.0 computer.I tried to install micro. outlook 2000, thinking it might just install itself over 98 but save the folders…
When the installation of 2000 is complete. I try to run 2000 but receive the following message:
DIRECTORY: Program Files\common files\system\mapi\1033\nt\omint.dll is not a valid windows nt image…..But the file is there.
I tried uninstalling and reinstalling w/the same message.. I than tried installing micro. outlook 98 back but received the same message….Any help would be appreciated..Is there any way for me to retrive my email folders I seem not be able to locate them………