kde-3.1.1a and net problem

[coollinuxer]

when I start KDE-3.1.1a it's halts the net
(any user)
ifconfig with no error
ping www.gentoo.org with no echo
# /etc/init.d/net.eth0 restart
wait for dhcp shutdown [OK]
start eth0 [OK]
then the net will be active

but for few minutes....the net is got the same error
and...there is no problem with gnome

My mainboad is EPOX-8RDA+,and I already install nForce driver

please help me
thanks!!