What do you mean by »free version of cs6«?
Welcome to the forum.
What was the URL, where you downloaded this "free version of CS6?"
Do you mean a "trial version," or something else?
Good luck, and please let us know a bit more.
Provided you are in fact not talking about pirated software—as there is no such thing as a "free" version of CS6—then the error message may simply mean that the connection to the Adobe server was down at that particular time for whatever reason.