Re: Error detected 1 426, 260.19.06, loss of VDPAU v-sync on second monitor
There were a number of VDPAU-related changes made in the 260 series, so I can believe you only started seeing this with 260.*.
I think we've essentially reproduced the second problem I listed above now, by running "kill -9" against MPlayer, rather than having it experience an error itself.
We'll keep trying to repro (1), and try to find out what the cause of problem (2) is.