Hello,
I have the same Event Viewer error on two different laptops running two different Microsoft accounts. All had the following install scheme: Windows 8 was updated to Windows 8.1 and then Windows 8.1 Update was applied.
I've clicked "Sync Licenses" in Windows Store, I can install applications from Windows Store just fine. WSReset.exe does not help, date and time zone are correct, Windows is activated.
In my case, the App Troubleshooter had returned three warnings:
One with permission settings that it had corrected (though probably unrelated to the issue as Process Monitor did not pick up any "Access Denied" events duing my tests)
Second with "corrupt files" but the SFC output was "Windows Resource Protection did not find any integrity violations." (which may mean that App Troubleshooter interprets the output wrong)
Third with display drivers that might be out of date (which is weird as they are from March 2014 and there is no update on Windows Update)

The Event Viewer message still appears.
Steps to reproduce:
instead of manually starting the task you can also start the following command:
rundll32.exe WSClient.dll,RefreshBannedAppsList
and check Event Viewer: Application and Services Logs -> Microsoft -> Windows -> Store Licensingfor the error message.