Outlook 2000 demands OE 4 or more recent to run

[Frank]

I use Outlook 2000 for managing my contacts on my Smartphone. When I
start Outlook 2000 I get an error message stating that Outlook Express
4.01 or a more recent version is necessary to run outlook. However, I
already installed the latest version of Outlook Express downloaded about
2 weeks ago. The error message then demands to install OE 5 through the
reinstall program of Office 2000 or to download OE 4.1 from the site of MS.
When I click on the OK button Outlook starts.
This error message is really weird. Is there any help to stop it?
Frank