Strange: windows auto-scan of pictures causes USB overflow/freeze

[mike-heal]

this one is bugging me... very interesting and odd behaviour.

So I have:
D2 w Rockbox patched firmware 3.59, 8MB unit
Win XP Pro SP3
Via USB 2.0 PCI card using via's specific drivers (not MS "standard enhanced EHCI driver" for 2.0 - that one causes me bluescreens on large file transfers to USB memory)
Old computer ASUS, P3 1ghz

So I plug in the D2 with the cord it came with, it connects to windows ok. I see the 2 drive letters appear.
Now, I'm browsing the BUILT-IN flash memory PICTURES directory.
(Removing or leaving in my SDHC card has no effect.)
When windows opens that directory, it automatically goes into "picture file" display mode, showing thumbnails of all the pics present, hitting the D2 up on every file.
I go one level deeper into another directory with, hmm, 150+files.
ONCE I HAVE DONE THIS, and all those thumbnails get pulled up real fast..
the file access gets BROKEN..
Any file I try to use- read, properties, delete, whatever, windows is STUCK.
Copying a new file to the D2 results in a "Parameter is incorrect" error and fails.
I can close the window (usually not responding) and try to see it again in explorer but the files are still stuck/broke.
It is IMPOSSIBLE to eject the D2 from the system tray- nothing happens!
The entire USB system is totally f'ed until I reboot.

I have to stay away from Windows doing its mass thumbnail rendering (use JetShell instead) to avoid this strangeness.
I've never had any other flash memory device act up like this, and my system is quite stable otherwise.

Any help on this? Is it a fault in poor quality D2 USB controller failing mass file-read requests? Anyone seen anything like this before..

Thanks