unable to ping other domain from clients

Hi,
I have a domain A(nt4.0 server) in one state and Domain B(win.2000)server in another state.
Domain B from the server, I can ping by name and ip address any address(computer) on Domain A. On domain B there are window 98 clients. They can logon to the domain(domain B), and can ping the server by name and ip address. But they are unable to ping any computer on Domain A. (There is a trust between 2 domains) Any help would be appreciated. Thanks.