I'm going to be doing a few posts about people who (thankfully) are very excited about starting a podcast. The good news they can't wait to launch. The bad news is they should. When you are running on 99% emotion you are going to overlook some things that can end up ruining your first impression. If you've ever received the message, “You must create at least one podcast episode for your podcast feed to be valid” then your cart is before your horse.
The problem here is you haven't uploaded your media (audio/video) to your media hosting (or a worst case your web host) and added it a post on your site. Itunes will have an issue when you submit your feed to iTunes.
Go back, and make sure you tag your files (or you will look like a hack), and then upload them to your media host like Blubrry.com or Libsyn.com (you can get a free month at Libsyn.com using the coupon code sopfree).
Add the media to your blog host using the PowerPress plugin (which will add a box to your post where you can copy and paste your link from Libsyn, or directly upload it to blubrry.com).
Is This You?
If you are thinking to yourself, “I need to upload my audio to iTunes” (you can't) you need some consulting. You are going to make mistakes and I would hate to see that happen to you.
I have tutorials at the School of Podcasting that will walk you through this whole process and get you going in the right direction.