Email from Excel Launches Setup Wizard

I have a few users who are seeing the email setup wizard launched whenever they try to email a spreadsheet directly from Excel 2000. They have a properly functioning email connection through an Exchange server and even have Outlook running minimized on the desktop but wtill get this wizard. Walking though the wizard doesn't necessarily mean that they can then use the feature either as they have almost always had it in the past and now don't. Any ideas?