You will find out you didn't really register this name. It will reject. I did the same thing, since www.Moniker.com allowed me too. I figured it was a 1/1,000,000 chance it would be true. It wasn't.
Read this thread all the way through, you will see why:
i love it when it when whois shows domains are available when they have been regged for years, i thought i had regged gold.info since domaintools showed it as availabe, im sure lots of others have done the same
I know that Eurodns has some bugs with .es too. Some names are incorrectly reported as available probably because the response from the registry is not handled correctly.
With .es certains names are reserved (reservado) while others are downright prohibited (prohibido).
Reserved names: spain.es and other geo names etc
Prohibited names: eta.es for example