I faced this error myself some time back and looked into it a bit, and here's what I have understood about the cause. If any Windows programming expert sees any egregious mistakes, kindly edit and improve.
Windows 8 and the introduction of the new Metro/Modern UI and apps necessitated several enhancements to the OS' security model. AppContainer is a new isolation method applied to Metro apps, which by default prevents them from both reading and writing to most of the Operating System, with the exception of the app’s own AppData folder.
Metro applications can make declarations in their application manifest file about which OS capabilities they need to access. You can read a bit more about this in the Delivering reliable and trustworthy Metro style apps article on the Building Windows 8 blog.
AppContainer is implemented through a new integrity level in Windows 8, supported by some additional changes to the OS. The AppContainer integrity level blocks both read and write access to objects marked with a higher integrity level. Now Windows Explorer normally runs in medium integrity mode, and explorer.exe is the parent process from which all other user-initiated processes inherit their access token. If Explorer is running with admin privileges i.e. at high integrity level, then any Metro apps it launches will inherit that administrative access token, which is obviously a strict no-no as it will violate the sandboxed environment provided by the AppContainer integrity level. Hence the error message thrown.