Adding Desktop Application "File required for desktop applications"

[PaulSweeney3]

Hi All

I have an issue adding a desktop application to ArcGIS online. i am met with the following error 

"File required for desktop applicitions"

can anyone tell me what is wrong here as I was under the impression it should be a zip file ? 

Thanks 

Paul 

[Brownschuh]

I'm running into the same issue as well.  Tried a few different zip files but encounter the error each time.