Internet connection, can ping,etc, but can't use firefox or safari?

When I try to open any of those 2 browsers it tells me that I am not connected to the internet. How; the network settings says there is no problem with the connection and I successfully tested the connection with ping and traceroute. I also noted that chrome works, I'm just curious why chrome would work and safari and firefox thinks I'm offline?

This is on a 10.6.8 on a iMac. I have limited information as to what caused this because its not my computer and it wasn't explained to me what occurred before the incident. what do safari and firefox do/don't that chrome does/doesn't?

(firefox is preferred in some respects due to the plugins available, especially the web to pdf plugin.)

 

if you mean are there DNS ip addresses listed, then yes, there were. I tried messing with locations but changed it all back as I didn't know what locations did or what they are for. Its usually set to automatic.