Okay everyone, I had the same problem for 5 days but after emailing Apple, they promptly emailed back with a solution. This worked perfectly for me.. It seemed the problem was that I had an outstanding order wich had not been paid for some reason, which stops you from downloading more apps until it is paid off. Follow the steps below.. This is the exact email i received from Apple.
1) Visit the Apple Store online:
2) Click Account in the upper-right corner, then click "Change account information" and sign in using the same Apple ID and password you use for the iTunes Store.
3) You should see your account-profile page. Under Method of Payment, remove all of the characters from the Card Number field. Do not change the expiration date or credit card type.
4) If you haven't already, select where you primarily use your purchases from the pop-up menu near the bottom of the page.
5) Click Continue. If you are asked to enter any other information, be sure to click Continue after making the updates so that your changes will be saved.
6) Make sure you're using the latest version of iTunes. It can be downloaded free of charge:
http://www.itunes.com/download Note: Installing the latest version of iTunes will not affect your library or any items in your account that you haven't downloaded.
7) Click this link to open iTunes and access the Apple Account Information page:
http://phobos.apple.com/accountSummary
8) Sign in to the iTunes Store using your account name and password.
9) On the Apple Account Information page, click the Edit Payment Information button.
10) Enter your payment information and click Done to save your changes.
*To ensure your account is functioning, you need to download a free item from the iTunes Store. To do this, navigate to the iTunes Store main page by clicking the Home icon near the upper-left corner of the window. Scroll down and click the "FREE ON iTunes" link near the bottom of the main page, then select an item to download.
Hope this helps everyone, worked for me!!
