Congrats, you just proved yourself wrong. Mr. Gervais is saying "prove I can't fly", and you're saying "prove there's no God". Both are negative statements. You're doing exactly what he's denouncing. It also shows that Mr. Gervais doesn't have a good understanding of what he's talking about either.
http://en.wikipedia.org/wiki/Argument_from_ignorance
I am saying "prove there is a god", not "prove there is no god." Why would I, an Atheist, ask for proof a god DOESN'T exist? You have the entire situation backwards.
Christians are the ones saying "prove there is no god."
In Ricky Gervais' quote, he is taking the position of a Theist stating "Prove there is no God" by saying "Prove I can't fly." Then the non-believer rebuts with "Prove there is a god!", or in the quote, "Prove you can fly!" Of course it would be silly to assume people should believe something that you have shown no proof of. Which is exactly what Christians get away with every day.
So yes, you can't assume "there is no god" to be a true statement because their is no evidence either way for it. So the best we can do is not accept ideas without proof. I have yet to see proof for the existence of god, so I until then, I will continue to not believe in gods.