Bought a Zoom X3 ADSL modem to use on my BT braodband, going through my Airport Extreme. Can't get it to connect. A friend set it up, and managed to get it to work, and 5 mins after he left, it gave me a "can't connect to server" message on any web page I tried to get onto. I pluged the modem into my ethernet port on my powerbook, and managed to connect, but again only for about 5 mins, then back came the message. The macs I have see my network, but I can't get on the net. Any help?