Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
iOS 6.1 Beta 5 is Released to Developers
The fifth Beta of iOS 6.1 has been released to developers by apple. You can get the new beta version on your iPhone, iPod touch and iPad and it includes a number of enhancements for both users and developers alike.
The new iOS Maps API’s which better integrate the mapping database into the app store apps and new features such as ordering movie tickets via Siri and improved lock screen media controls have also been included in the new beta version.
iOS 6.1 has not yet got a public release date and mac-reviews.net will keep you 100% informed on any developments with this issue.
There has been some recent information coming over twitter with regards to the new beta including talk of activation without developer registration, no ReleaseType lock-down keys and the fact that at least one point the activation code name was rather odd!