Unable to accept or update Apps

Hi there,

I recently purchased a new Mac Mini Server with pre-installed OSX Mountain Lion.

When I go to the App Store, it says that I need to accept 4 Apps (i.e. Garage Band, iMovie, iPhoto, OSX Server). When I click on the Accept button, nothing happens and I get the following in the console logs.

Feb 21 13:09:26 server.home.private storeagent[667]: <AdoptOperation: 0x7f91f9a232e0> caught *** setObjectForKey: object cannot be nil (key: serial-no) exception with stack trace: (0x7fff8492008e 0x7fff88afa3f0 0x7fff849ae897 0x1100154a8 0x110015bbf 0x1100a9e72 0x1100a99b0 0x7fff8e09c986 0x7fff8e0a41a1 0x7fff8b1faf01 0x7fff8b1f70b6 0x7fff8b1f81fa 0x7fff82a12cab 0x7fff829fd171)

When I try to update the Apps it gives me the error "There was an error in the App Store. Please try again later. (null)" and the console logs outputs the same message.