2.4: "kernel: hw tcp v4 csum failed" with e100

I've switched from the eepro100 driver to the e100 in 2.4.22-rc2 and
started getting "kernel: hw tcp v4 csum failed" in the logs. Going
back to the eepro100 makes these messages disappear. The machine is
a dual-pentium with the Supermicro DE6 motherboard, which comes with
the Intel ethernet chip on board. ifconfig shows no ethernet errors.

What's the meaning of this warning? I grepped the kernel sources and
found nothing. I'm not even sure it's net-related; I apologize if this
isn't the correct list.