I personally think its just down to Virgin
I inputted all our details, baring in mind we are a family of 6, Dh and I, DS8, DS7, DS4 and DD2.
It kept saying exactly the same thing to me, I just kept redoing it over and over again, refresh, refresh, refresh, finally accepted it on my 18th attempt I think.
As you can see by how young our children are, airports can be fairly stressful and therefore I will spend all day trying to do something on my own at home rather than take 10 minutes out doing it at check in with all my highly excited children.
One of the main reason we upgrade everytime we fly is down to the speed at the airports, the less time I'm messing about in them the better. To be fair I'm not doing my children much justice there they are great kids I'm just a terrible flyer