Windows 2000, HOST files, and AS400?

Here is my question. I have a PC with windows 2000 Professional on it. We use both Lotus notes/ Domino for the AS400 and Client access for the AS400. Under windows 95/98, all we had to do was place a HOSTS file manually in C:\windows. This does not work in wndows 2000. The LMHOSTS files do not work. No matter what we do, it will NOT see the tcp/ip of the as400’s in hte program set ups. I can ping them, but it refuses to see them. Can anyone help? Its worth 245 pts since that is how much Microsoft wants to support windows 2000. LOL