Hi all, I wasn't aware of this thread when I posted the AR7 info. That issue should only affect the DSL connection itself and shouldn't affect the (w)lan side of things at all. Having said that, it is supposed to be a router on a chip...
I know you said you'd set the card to "100Base-TX", but was there also a duplex setting? If so, set it for full.
A fairly useful utility, seems to log everything and displays it nicely with a description of the event etc. See what XP thinks your connection is doing.
http://www.eventlogxp.com/
Good luck with the "Burn".