> So, it's not your data. I would check if
> "Our very Long Product Name Path" takes the number
> of characters over 256? Do a test with just under
> 256 - I think I've read about this.

Its long, but its well below 256 chars , rather around 70 chars including the name of the temporary file.

>
> You didn't mention your OS?

So far I've tested this on:

Windows Vista 32 bit
Windows Vista 64 bit
Windows 2008 64 bit

and managed to reproduce the same result.

I'm now preparing the same test on a 32 bit Windows XP machine.