John,
Don't worry, we will figure out what it is.
I do want to verify one thing. Don't bother to post it, but please verify that you can't traceroute to 198.80.11.57
This does indicate something is not right and you should be able to verify this by connecting via telnet to route-server.ip.att.net and route-server.exodus.net and using the traceroute command there where it should work all the way through - a different result than from your PC.
John