Use of the virtual card has nothing to do with the country you are.
Some merchants does not accept the virtual card for various reasons for example because its a debit card or issued in another country than you are in.
I am sorry but I don't know if its possible to use at Google Checkout but you should be able to use it at Adwords, if you have problems using it at Adwords please send me a email with your UserID and the day/time you last tried.
Thanks
Michael
[email protected]