pgAdmin II connection problem

hi all,

i would like to connect the postgreSQL from a remote hosts, but fails, here
's the detail.
Did anyone know what's going on?

postgreSQL : 7.2.2
OS : RedHat 7.3
ip : 192.168.1.195

remote host :
OS : windows XP
ip 192.168.1.204

i added follwoing  line in  /var/lib/pgsql/data/pg_hba.conf
host       all         192.168.1.204 255.255.255.0      trust

PS : attached with error msg from pgAdmin II
"An error occured in pgAdmin II:frmConnect.cmdConnect_Click:
Number: -2147467259
Description: Could not connect to the server;
Could not connect to remote socket."