Hello
I had the same error. Here is how I fixed it.
Reset all APPERY code changes and export app. Make sure you have all the images under ios binary - icons in appery
in Xcode - goto you app in left column and look for the folder called ICONS. ITS LOCATED under RESOURCES - ICONS
RIGHT CLICK ON THE FOLDER named ICONS
LEFT CLICK ON Add Files to "YOUR APP NAME"
Window will appear and it will allow u to select the Icon-60.png
Select the file and the problem is solved.
i just did it and posted my app to APPLE.