Sferical, i've tried your suggestion and thanks!!
The Blackberry browser is now working. The user can now browse using the blackberry browser. But the MDS is still hanging with error.
The error message is still the same "There are errors in retrieving data from the server. Please refer to the log for more information".
The security admin has opened the TCP Ports : 80, 8080, 7080, 7443, 7005, 3200, and 1433 in proxy server. But still no luck. The MDS is still error. We're using isa server 2004, and I forgot to tell you, there is a router/firewall in front of the proxy server. Do these ports need to be opened in router/firewall too? Anyone has some suggestion? Thanks in advance.