wireless connection OK, DNS error all pages

Windows XP
IE 6.0
P4 2.6
512mb

No problem day 1: integrated Dell mini pc card (8012.11 b/g) connected fine to a network at a home I'm visiting. No problems using the internet.
Problem day 2, I used my PCMCIA Sierra wireless aircard to gain internet access on the road. Come back to friend's house and got IE DNS error or page cannot be displayed.
Day 3, tearing my hair out trying to figure this out! I have a strong (11 mbps)established wireless network connection, but continue to get DNS errors. Am getting "request timed out 4 packets sent and lost" errors when trying to ping 192.168.0.1.

I have rebooted the computer. Rebooted the cable modem and Linksys wireless router. What the heck happened, and does anyone know how to fix it? Also, I can get a wired connection (friend's ISP is Roadrunner) but get the same DNS error. If I go back to my wireless mobile card I can get online and open pages, but it's so slow I would rather get the other way working.
Thank you.