losing network connection
 

I have a PC that keeps dropping network connection when under any kind of load. It is a Davicom integrated NIC. So I installed a Lynksys NIC that I had no problems with, but this card does the same thing. I started looking at the files in /var/log. I posted a part of the syslog that I thought looked weird. Can anyone tell me what a dirty pointer is and if it is what causing my problem?
Thanks
Dec 17 16:44:15 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:44:15 server1 kernel: eth1: 21140 transmit timed out, status fc740000, SIA ffffff7e 0000dc00 0000dc70 fffffec8, resetting...
Dec 17 16:44:15 server1 kernel: eth1: transmit timed out, switching to MII media.
Dec 17 16:44:17 server1 kernel: eth1: Setting full-duplex based on MII#1 link partner capability of 45e1.
Dec 17 16:44:23 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:44:23 server1 kernel: eth1: Out-of-sync dirty pointer, 1043 vs. 1060.
Dec 17 16:44:39 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:44:47 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:44:47 server1 kernel: eth1: Out-of-sync dirty pointer, 1059 vs. 1076.
Dec 17 16:45:03 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:45:11 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:45:11 server1 kernel: eth1: Out-of-sync dirty pointer, 1075 vs. 1092.
Dec 17 16:45:39 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:45:47 server1 kernel: NETDEV WATCHDOG: eth1: transmit timed out
Dec 17 16:45:47 server1 kernel: eth1: Out-of-sync dirty pointer, 1091 vs. 1108.