This error will be very common for people working with Windows Store application, and Windows Phone 8.

Is just an Asynchronous programming common mistake.

It happens in methods declared for example in following way:

 

public static IAsyncOperation<string> GetDisplayNameAsync();

 

For calling this method you are NOT able to call it for example:

string displayName = UserInformation.GetDisplayNameAsync();

 

Solution would be just adding await when calling the method:

string displayName = await UserInformation.GetDisplayNameAsync();

 

For more information about asynchronous programming,  please go to next URL:

http://msdn.microsoft.com/en-ie/library/hh191443.aspx

 

See you soon.