Network card error

I’m getting this

eth0: Transmit timed out, status 0000, PHY status 786d, resetting…
eth0: link up, 100Mbps, full-duplex, lpa 0×45E1

with my

eth0: VIA Rhine II at 0×1e000, 00:04:61:50:57:68, IRQ 193.
eth0: MII PHY found at address 1, status 0×7849 advertising 05e1 Link 0000.

in my syslog about every 10 seconds during heavy uploads, but not during downloads.

Does anyone know what’s going on?