I can’t access a Windows XP based website via Windows 98/Frontpage 2000

My customer is using Windows 98 and FrontPage 2000 cannot access the website I developed for a customer using Windows XP.
They get an error message reading that the website is not FrontPage enabled. I have confirmed that the site is indeed FrontPage enabled, since I can connect using my windows XP. Infact I can successfully publish to that website.
Are there any suggestions so that my customers using Windows 98 and FrontPage 2000 can access this website too?
