Not able to start project

Hi, I just downloaded the app from the Mac App Store, running on a Mac mini, when I get the prompt to choose a project I select one and click choose, the buttn dims for 10 seconds an nothing happens, I get the same type if thing trying to set folder authorisation.
My mac is set up with the user directories on a secondary external drive.
The app works fine on my Air.
Please help.

It sounds to me as though the sandboxed file dialogue boxes are failing silently. Do you have similar results in other sandboxed applications? Apple’s TextEdit in 10.8 (and maybe 10.7 as well) is sandboxed. Can you save files using it?

Also open up Console, from your Applications/Utilities folder, and watch that while trying to set the folder authorisation in Scrivener. Do you get any error messages?