tcpi/ip dies at random times

My inet connection dies at random times (see example below) the only
way to repair is a hard reboot (and hard reboot of cable modem)...
this problem only started appearing after switching from i386 to amd64

uname -a:

FreeBSD monsert 7.0-CURRENT FreeBSD 7.0-CURRENT #3: Mon Oct  1
02:06:20 UTC 2007     aryeh_at_monsert:/usr/obj/usr/src/sys/GENERIC
amd64

Problem output:
monsert# cvsup /usr/share/examples/cvsup/ports-supfile
Connected to cvsup10.us.FreeBSD.org
Updating collection ports-all/cvs
 Edit ports/LEGAL
 Edit ports/MOVED
 Edit ports/UPDATING
 Edit ports/audio/qjackctl/Makefile
 Edit ports/audio/qjackctl/distinfo
 Edit ports/audio/qjackctl/files/patch-src-qjackctlSetup.cpp
TreeList failed: Network write failure: Connection closed
Will retry at 15:37:45monsert# ifconfig -a
re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
        ether 00:19:db:b5:f8:0f
        inet6 fe80::219:dbff:feb5:f80f%re0 prefixlen 64 scopeid 0x1
        inet 67.84.39.90 netmask 0xfffff800 broadcast 255.255.255.255
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> metric 0 mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        inet 127.0.0.1 netmask 0xff000000
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3

relevent sections of dmesg:

re0: <RealTek 8168/8111B PCIe Gigabit Ethernet> port 0xe800-0xe8ff mem
0xfcfff000-0xfcffffff irq 17 at device 0.0 on pci4
re0: Using 2 MSI messages
miibus0: <MII bus> on re0
rgephy0: <RTL8169S/8110S media interface> PHY 1 on miibus0
rgephy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseT,
1000baseT-FDX, auto
re0: Ethernet address: 00:19:db:b5:f8:0f
re0: [FILTER]
re0: [FILTER]

No abnormal entries in /var/log/messages