This is probably a temporary server problem with the AG website Rageness113... just make sure you have enabled your cookies for ArmorGames and accept (for some games) a larger datasave for your flash player for ArmorGames. If this is all set correctly, I advise you to just keep trying again and I'm sure you'll get in.
If it should persist though, contact justin (AG admin) about it via email, support@armorgames.com, and he can help you further in solving the problem, ok? =)