Unable to browse server on remote domain by IP but can by FQDN

A bit of a strange one this. I have got a server in domain A which all clients in A can browse with no problems.

Clients in Domain B (another domain within the forest) however can ping in by IP or FQDN. But can only brwose the servers shares by FQDN, not netbios or IP. With the error Message

You might not have access to this network resource
There are currently no logon servers available to service the logon request.

Server is windows 2000. And clients in domain B can browse other servers in domain A without any problems.

Any suggestions much appreciated