Ping Time out

I tried pinging my server from one of the workstation but it returns “requests time out” but when i tried pinging that workstation from other workstations the ping return is positive, i checked the cable with a cable tester and the cable is good too, we have a program running from that workstation which needs to be connected to the server but inasmuch the connection fails, we cant run the program (oracle based system). Your immediate reply on this regard will be highly appreciated. thanks