Packet corruption in re0

I am experiencing roughly 15% packet corruption on the re interface on
my freebsd 7/amd64  box.

FreeBSD gw.flexi.robbak.com 7.0-PRERELEASE FreeBSD 7.0-PRERELEASE #8:
Tue Feb  5 09:49:55 EST 2008
root_at_gw.flexi.robbak.com:/usr/obj/usr/src/sys/GW  amd64

The attached 3 files demonstrate the problem: "ping" shows the output
of ping -c 100, and shows 15% packet loss. "tcpdump" shows the packets
leaving, and some of the lost packets being returned with addresses,
ports and data corrupted. The data in these packets seems to be coming
from other packets passing through other interfaces at the time.
"remote-tcpdump" shows the packets being received and returned from
the other machine. Note that some packets are being corrupted on the
way out, too.

Just to make troubleshooting difficult, this problem only shows up
after the system has been up for roughly 36 hours, depending on the
amount of traffic.

I am using the latest bios that I am aware of. The bios that I
recently applied did include a firmware update for the realtek
interface, but this did not affect the problem.