I just tried to book AF using virgin points... went all the way through to the payment stage, and then said the fare had changed and failed.

Called Virgin customer services who said he is quite frustrated because they've reported it several times, but still happening.

He said (not sure if true) that Virgin is showing award availability for Air France members, rather than what's available to partner airlines. So it shows available on Virgin, but they are not able to book. But if others are having success through the call centre, I'll try again.