Windows to Linux networking problem

Hi,
We have a redhat server and a windows 98/2000 workstation. We have 5 users setup in the server. when 4 of them logon to the workstation they are able to see the server and access it. Only one person cannot access the server though she can see it in her logon. When she tries to login to the server, it asks for a password. she gives her username and password but it says that it is invalid. all her settings in the linux server are similar to others. when she logs in her name at the server she doesnt have any problems.
My conclusion is:
Her user setup in the server is fine.
The problem seems to be in the authentication sent from her windows machine to the linux server.
Can anybody help me on this please?

lamrin