I have the latest Jaunty and I am getting the same message. 

[175559.988029] ------------[ cut here ]------------
[175559.988038] WARNING: at /build/buildd/linux-2.6.28/net/sched/sch_generic.c:226 dev_watchdog+0x219/0x230()
[175559.988044] NETDEV WATCHDOG: eth0 (r8169): transmit timed out
[175559.988049] Modules linked in: binfmt_misc dvbloopback bridge stp bnep video output input_polldev nfsd auth_rpcgss exportfs nfs
lockd nfs_acl sunrpc xfs lp snd_hda_intel snd_seq_dummy snd_seq_oss snd_seq_midi cx88_alsa snd_rawmidi snd_pcm_oss dst snd_mixer_oss
 ppdev nxt200x dvb_bt8xx bt878 cx88_dvb cx88_vp3054_i2c nvidia(P) tuner_simple tuner_types snd_seq_midi_event snd_pcm k8temp snd_seq
 agpgart snd_timer tuner psmouse pcspkr serio_raw snd_seq_device bttv cx8800 cx8802 cx88xx snd ir_common videobuf_dvb i2c_algo_bit d
vb_core videodev v4l1_compat compat_ioctl32 v4l2_common videobuf_dma_sg tveeprom videobuf_core btcx_risc soundcore snd_page_alloc pa
rport_pc parport lirc_atiusb lirc_dev usbhid ati_remote r8169 mii ehci_hcd ohci_hcd fbcon tileblit font bitblit softcursor fuse
[175559.988163] Pid: 0, comm: swapper Tainted: P           2.6.28-8-generic #26-Ubuntu
[175559.988169] Call Trace:
[175559.988181]  [<c0139a70>] warn_slowpath+0x60/0x80
[175559.988190]  [<c040caaf>] ? pci_read+0x2f/0x40
[175559.988201]  [<c02cce26>] ? pci_bus_read_config_word+0x66/0x80
[175559.988210]  [<c0156863>] ? getnstimeofday+0x53/0x110
[175559.988218]  [<c01199f3>] ? lapic_next_event+0x13/0x20
[175559.988226]  [<c0159a9a>] ? clockevents_program_event+0x9a/0x150
[175559.988233]  [<c0156863>] ? getnstimeofday+0x53/0x110
[175559.988241]  [<c02c1a4d>] ? strlcpy+0x1d/0x60
[175559.988249]  [<c04199f2>] ? netdev_drivername+0x32/0x40
[175559.988255]  [<c042e559>] dev_watchdog+0x219/0x230
[175559.988262]  [<c0151a9a>] ? hrtimer_forward+0x12a/0x170
[175559.988268]  [<c0156863>] ? getnstimeofday+0x53/0x110
[175559.988275]  [<c01199f3>] ? lapic_next_event+0x13/0x20
[175559.988282]  [<c0159a9a>] ? clockevents_program_event+0x9a/0x150
[175559.988291]  [<c0143a90>] run_timer_softirq+0x130/0x200
[175559.988297]  [<c042e340>] ? dev_watchdog+0x0/0x230
[175559.988302]  [<c042e340>] ? dev_watchdog+0x0/0x230
[175559.988311]  [<c013f137>] __do_softirq+0x97/0x170
[175559.988316]  [<c0152c26>] ? hrtimer_interrupt+0x186/0x1b0
[175559.988324]  [<c013f26d>] do_softirq+0x5d/0x60
[175559.988330]  [<c013f3e5>] irq_exit+0x55/0x90
[175559.988336]  [<c0119ffb>] smp_apic_timer_interrupt+0x5b/0x90
[175559.988345]  [<c0105318>] apic_timer_interrupt+0x28/0x30
[175559.988354]  [<c0121f35>] ? native_safe_halt+0x5/0x10
[175559.988360]  [<c010afbd>] default_idle+0x5d/0x60
[175559.988366]  [<c010b0b6>] c1e_idle+0x46/0x120
[175559.988372]  [<c010285d>] cpu_idle+0x6d/0xd0
[175559.988380]  [<c04e6d4e>] start_secondary+0xbe/0xf0
[175559.988385] ---[ end trace cf92d500d99a889b ]---
[175560.009273] r8169: eth0: link up


lspci -vvv

03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)
        Subsystem: Biostar Microtech Int'l Corp Device 2305
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 2295
        Region 0: I/O ports at ac00 [size=256]
        Region 2: Memory at fddff000 (64-bit, non-prefetchable) [size=4K]
        [virtual] Expansion ROM at fdc00000 [disabled] [size=128K]
        Capabilities: <access denied>
        Kernel driver in use: r8169
        Kernel modules: r8169