After installing 2000 server

After installing 2000 server, setup using a workgroup not AD and a share with the default settings (everyone full). A win98 client runs a program on the share and when it completes a task it starts a small conversion program running and then imports the data into its database. It fails when it tries to convert the data and import. It worked when the application was on PC (Server) with Win98 installed. Any idea about what to try to change would be great.