Windows NT 4.0 server

I am working with a network that has Windows NT on the server and Windows 98 on the clients. It’s set up on a single domain with 5 workstations. The server has an Access 2000 database file that is set up to be shared by the clients. When the fileis open, each client is able to access it, however, when each client makes changes to the database, the file is saved to the client instead of the server. When another client accesses the file, it doesn’t have the updated file on the server. Can you tell me why? I am open for suggestions.
Thanks
Randy Thaves
email R.Thaves@worldnet.att.net