Vista - Revisiting the Buffalo NAS vs. Vista problem...

I have two Buffalo NAS models (details below) which have been working fine for over 6 months with the following PCs: 2 running Windows XP Pro, 1 running Vista Home Premium (x32), and 1 running Vista Ultimate (x32). I never had a single problem with either NAS under this setup (wired/wireless via Belkin 55g router).

Last week I added a new PC running Vista Home Premium (x64) and didn't have any problems until I replaced its OS with Vista Ultimate (x64), via a clean install. NAS Navigator detects both NAS and seems to successfully mount the shares, but accessing any file causes Windows Explorer to hang, requiring a restart. I can navigate the directories (albeit very slowly), but if I try to open/move/copy a file, Explorer crashes.

Now here's the really weird part-- I also run Virtual PC 2007 on the same x64 machine, using XP Pro x32 as the guest OS. It works perfectly with both NAS units!

The firewall/security is turned off completely (was running NIS 2009), btw.

I've tried the registry key hack mentioned elsewhere in the forums, and have reset all the hardware multiple times, but no joy...

What should I do next?

Any help is greatly appreciated!

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NAS 1 -- Buffalo LS-W1.0TGL/R1-V3, firmware v3.07
NAS 2 -- Buffalo HD-HLAN, firmware v2.05
Software -- NAS Navigator v2.18
Router -- Belkin 55g (wired connections)
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