Rather than show a pop-up when you try to vote your own question or answer up or down, just don't show the vote buttons - much like how there's no upvote button on your own comments.
I agree with ChimneyImp. Not many new users come in to Meta to ask that, and those that do will find out very quickly that they simply can't vote on their own question
Yes this is a great idea then we just have to update out FAQ with this that
You can't upvote your own post even it is answer or question
Or community can point out with a separate FAQ like
Why I'm unable to see the Vote button on my own post while others posts I can?
and the answer could be more powerful then mine
You can't vote to your own post so you are not able to see those buttons for your own posts.
I don't even have enough rep to upvote your question, but I would. I guess it should also be said that if the user does not have enough rep then the upvote button should not be shown
Having the buttons there provides the option for a learning experience.
You click them once (just for fun, of course), and it instantly tells you that you can't do that.
Lesson learned, all is good.
If the buttons were not there in the first place, you might wonder why they aren't there.