That's complete bullsh!t.
It is execution that matters. Ideas are a dime a dozen. What google did was excellent execution of an non-original idea (there were lots of search engines at that time).
Look at the UConnect vs. Facebook. vs. that other dude that that the same idea.
Facebook was able to execute much faster and better and got traction, while Uconnect is just crap, and they have to resort to lawsuits.
Sure, if your idea is dumb to begin with, then no matter how good the execution is, you wont get anything out of it.
But you still can change ideas and business plans around, and from a loser make a winner offering. (many startups end up changing their ideas business models at some point, including the company I am working for).
If your execution team still sucks, your products will show it, and the next guy that likes idea, will copy it, and make a much better version of what you are offering. (just like Friendster got hosed by poor execution).
But it is a common trait from "Business" people that think ideas matter more. It is more of a whishful thinking. Honestly being good at business is nothing more that having a good common sense and street smarts, and knowing how to B.S. a little. Things that no school teaches you.
So my advice, learn how to build websites (as a programmer I'd like to concetrate on the harder stuff), do everything you can help the whole team, (from marketing, getting graphics, building mock-ups or prototypes) etc.. While you don't have to program, you better have some good technical skills, and really understand what's going on and how hard or easy is to do some stuff.
One thing that is very annoying, is how non-technical people think it is sooooo easy to just have an ajax drop down, or that little thing here, that little thing there, without having the slightly idea how much work it really takes.