thanks for pointing out these issues to me, mine seems to be similar.
Unfortunately the first pre-185 version gentoos portage system has to offer is 173.14.28
which doesn't support VDPAU...at least vdpauinfo dies with a short message,
saying that the vdpau libraries are missing.
Anyway I attached the bugreport generated with 173.14.28.
So I have these to offer for trying out:
If it's worth investigating to you/nvidia,
I could send my card, if I could get a replacement
whilst mine is out of country - (it's the only PCI-E I have)
...but since it seems that at the moment
I'm the only one hit by this error code, i guess it's not worth it.
But maybe you have a reference VGA-BIOS around somewhere,
that i could flash, after checking the timings and clocks?
I think you were asking abut the memory type on the other thread, mine is a DDR2.
If you think a new BIOS might help, I dare to fry my card and decorate my flat with it.