Problems with 2.6.8.1 kernels

For some reason, I can't get 2.6.8.1 kernels to work. Not just kernels I've compiled myself, but also the stock redhat kernels in the Fedora Core 2 updates. The problem lies in the networking. Everything else seems ok, but I can't get the network card to work. I keep getting the message below:

Oct 17 10:45:01 gizmo kernel: eth0: RealTek RTL8139 at 0xe000, 00:e0:4c:10:20:ce, IRQ 11
Oct 17 10:45:01 gizmo kernel: ip_tables: (C) 2000-2002 Netfilter core team
Oct 17 10:45:01 gizmo kernel: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Oct 17 10:44:57 gizmo sysctl: net.ipv4.conf.default.rp_filter = 1
Oct 17 10:44:57 gizmo sysctl: kernel.sysrq = 0
Oct 17 10:44:57 gizmo sysctl: kernel.core_uses_pid = 1
Oct 17 10:44:57 gizmo sysctl: kernel.shmmax = 134217728
Oct 17 10:44:57 gizmo sysctl: net.ipv4.tcp_ecn = 0
Oct 17 10:44:57 gizmo network: Setting network parameters:  succeeded
Oct 17 10:44:57 gizmo network: Bringing up loopback interface:  succeeded
Oct 17 10:45:09 gizmo kernel: NETDEV WATCHDOG: eth0: transmit timed out
Oct 17 10:45:09 gizmo kernel: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
...
Oct 17 10:45:33 gizmo kernel: NETDEV WATCHDOG: eth0: transmit timed out
Oct 17 10:45:33 gizmo kernel: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1
Oct 17 10:45:45 gizmo kernel: NETDEV WATCHDOG: eth0: transmit timed out
Oct 17 10:45:45 gizmo kernel: eth0: link up, 100Mbps, full-duplex, lpa 0x45E1

It's not ECN, which is explicitly switched off in by sysctl.conf Anyone got any ideas?

UPDATE: I've sorted it out. Set noapic on the command line in /etc/grub.conf, and set 'Plug and Play OS' to 'No' in the BIOS.