Not able to access shared resources

hello
I have one system where i installed windows server 2003 with firewall configured.
ipaddress of the machine is 192.168.10.2.and i have 3 other system who’s ip address are 192.168.10.5,192.168.20.4and 192.168.30.6 respectively.i m able to ping server from all the system.i m able to access shared resources in the server from 192.168.10.5 machine but not able to access from 192.168.20.4 and192.168.30.6 machine.
all the systems are in workgroup.

please anyone solve this!!!