Happy 2014 New year began with an Error. :D
ErrorDetail: There was a problem with activating the app web definition.
ErrorTypeName: App Related
ExceptionMessage: Exception from HRESULT: 0x81070964
SourceName: App Web Deployment
This error occurred to me suddenly and i have lost with my development. Then i found a file (.json) which i included to the project gave this error. I found that some file types which are not supporting may caused this error.
Happy 2014 and May every code work for you!