In Group Policy (gpmc.msc), edit the Domain Policy.
Computer Configuration, expand Windows Settings, expand
Security Settings, expand Local Policies, and then click
In the list of available policies, double-click
Network security: Do not store LAN Manager hash value on next password change, and then Disable that policy.
Make sure that a WINS server is running on your network.
Make sure that the Windows 98 client is enabled to use WINS and the local domain DNS server.
Change the password of the user account that you plan to use to join the Windows 98 client computer to the domain. This enables the password to use a LAN Manager hash.
Try to join the Windows 98 client to the domain.