Help with 5.1-beta snapshot

(I'm using the 5.1-beta .iso snapshot from 0521)

Basically, I think I'm missing something painfully
obvious but i can't figure out what.

I've got an Asus A7V8X which has a Promise 20476 on
it, which doesn't work in 5.0, so I have to go newer.

Well, everything works but I can't get a network connection up.
I've got a bge0, a de0, and an rl0 (I tried everything I had :)
and different cables to different switches.  The link lights
indicate a link, the ifconfig line shows that it detected the
link speed/duplex properly, but I can't ping or make a tcp
connection.  the rl0 and bge0 give me "watchdog timeout : resetting"
whenever I ifconfig up them, and the de0 just plain doesn't do
anything.

Any suggestions?  I feel I'm missing something stupid but I can't
figure it out, and I can't see anything in the current archives
that lead to this (but feel free to point it out if I missed something :)

It's a KT400 chipset board, if that makes a difference.

(I'm using the 'stock' kernel : I'm going to recompile it and see
if that makes a difference later today.)

Thanks

Dana Lacoste
Ottawa, Canada