IO Error 64 on 64bit Win7 networked machines

[Ct198]

For the last couple of weeks I've been getting the following error with my utorrent client (2.0.3):

"Error: The specified network name is no longer available."

This only occurs when downloading from the utorrent machine to a shared folder on the storage machine (an XBMC HTPC). There seems to be no specific type of torrent that is affected beyond that.

The logger says:

[2010-08-08 10:44:22] IO Error:64 line:419 align:1 pos:6112288 count:16384 actual:-99

[2010-08-08 10:44:22] IO Error:64 line:675 align:512 pos:6112288 count:16384 actual:0

..among many other "IO Error:64"'s.

I searched for this error and found a few other threads, but none that have solved the issue (or have told me how anyway).

Things I have tried include:

- checked write cache enable

- checked read cache enable

- checked windows write cache disabled

- checked windows read cache disabled

The shares are available, even when the issue is still occuring so the network should be fine. I'm guessing maybe it has something to do with Win7 thinking the downloading machine is DDOSing it. But if I click "Start" on the torrent with the error it will immediately start seeding again until the issue returns (usually within a couple hours). I made sure that EnableConnectionRateLimiting was not in my registry so that Windows would not limit connections on both machines. Now I'm at a loss.

HijackThis log:

http://www.zshare.net/download/7952368902599e20/

ProcExp log:

http://www.zshare.net/download/7952369510c59578/

Equipment:

i7 920 Win 7 Ultimate 64bit Rig

Phenom II Win 7 Ultimate 64bit HTPC

Linksys WRT running Tomato

Can anyone please give me insight on what could be causing this sudden issue?

[paintball9]

Does it seem to happen on intervals? Say 10 minutes or so. It could be the hd on the second machine is going to sleep only to be woken up again but the delay is long enough that utorrent thinks the machine is gone. I've had network outages of similar results that were dealt with by disabling spin-down on the drives. The only downside is the loss of power-saving function and possible drive life span. (if that fixes the problem at least)

[Ct198]

Not going to say for certain that that could not be the issue, but I am doubtful. I leave the HTPC running 24/7 and utorrent on the Rig as well, with about 300 torrents seeding and 10-20% of those are going to the HTPC. The hdd should always be spinning while seeding the non-error files, yes?