Cannot validate your password

Hello,
we are running windows 2003 server with 98/Me/XP clients on the network. Recently i updated latest updates. From that day I cannot log on to the server with 98/ Me clients.
I am getting error message as follows
“Cannot validate your password”
What i did is
1. I installed DS client on windows 98/Me boxes- same thing
2. I release Ip and renew ip. same thing. But i assigned static IP.- Same thing
3. Deleted adapter and reinstalled. – Same thing
4. I added server address in host and lmhost files -same thing
Please help me out what i need to do?