Comment 43 for bug 573259

am experiencing the same issue it seems
running 11.04 64bit, have a RTL8111/8168B network card

I seemed to be able to "fix" it by unplugging/plugging in the network cable a few times and then it would suddenly connect
this had to be done every startup

now I found a workaround through this link:
http://ringlord.com/news-20110429.html

I added following command to /etc/rc.local
ifconfig eth0 down
sleep 10
ifconfig eth0 up
sleep 10
ethtool -s eth0 port tp

and now my 11.04 is connected automatically before I'm logged in (so when it's still on the logon screen)