unable to ping

i am having one problem please help me to solve it in our premises
we have 192.168.1.6 /255.255.255.0 & 192.168.1.9 /255.255.255.0 as a DNS server i m having one machine with IP adress 192.168.1.19 & another system machines with IP adress 192.168.1.85 & 192.168.1.91 its our administrators machine . problem is that when i use ping command from 192.168.1.19 its pinging itself ,DNS server & 192.168.1.91but unable to ping 192.168.1.85 when i want to ping 192.168.1.19 from any machine on network its not giving any reply