What i gave you was the alpha and the numeric for the same server. Sounds like someplace there is a dns problem, perhaps at your isp.
for every ip there is an alpha and a numeric.... since its far easier for ppl to remember something like brat.pb.net than 123.456.789.432 (both made up, so dont try to use those, lol) when you type in /server brat.pb.net some lil gremlin resolves/translates that domain into 123.456.789.432. (dns is domain name server) Your lil gremlin is asleep someplace along the line.
To get the numeric, while i was connected to that network, i typed: /dns b0rk.uk.quakenet.org and was shown the numeric for it. I could also have typed /dns 188.8.131.52 and it would have told me b0rk.uk.quakenet.org. If you look at all the stuff that scrolls thru your window when you connect, you will prolly also see the numeric. So, go to the website i told you, find some servers, then get the numerics for them and write them down someplace