I sent them a little note:
Got my new MacBook Pro 17" today. The only thing I transferred from my old powerbook were my network settings.;-)
Then, when I tried either the direct connect Etherenet cable to my Linksys router, or my Airport, neither worked.
Why oh why did I transfer those network settings?
Then I read through the messages here and saw a pointer to a tip to completely power off the cable modem, router and airport, and MacBook Pro.
After doing that and resarting everything, both internet connections work.