Currently Being ModeratedJun 17, 2011 4:33 PM (in response to JazzHot)
I finally got it to work.
My problem was Spotlight !!!!!!!!
I disabled a while ago Spotlight upon an advice that when you use Logic Pro on a professional basis like I do, it was better to turn off Spotlight. To do so I used Spotless.
I turn it back on and gone was my problem not being able to download anything from Mac App Store.
Hope this work for others.