I guess you're talking about one of my games? No, you cannot add anyone else's games other than your own on ArmorGames. It's just how that sort of thing works ^^
Specifically regarding Mine Blocks, many years ago I unfortunately couldn't reach a good agreement with ArmorGames. I didn't want to do it for them paying me a one-time license - it seemed like a generally unfair deal. I guess I'm more making a statement about their business practice (at the time the offer was denied, at least - it's possible they changed their ways) by not giving them the license.
Thanks for your wanting to help though, I really appreciate that! :)