Build with VoltBuilder = Error: pngload_buffer: libpng read error

Does any one know what this error message means:

error: ERROR: pngload_buffer: libpng read error 
pngload_buffer: libpng read error
vips2png: unable to write to target target
vips2png: unable to write to target target

Where does this message appear?

After I click Make Native App with VoltBuilder, it pops up in AppStudio.

If I click OK it still builds the app ok, it doesn’t seem to do it every time, just now and again.

Have a look at the images in your app. Are they all set up properly?

Just checked, they seem to be. I don’t get the error all the time and it doesn’t seem to effect the build, I just wondered what is was.

Some times I also get “cant find icon.png” but when I check it is there, to fix it I have to go to the properties panel Icon field and re-select the icon again, even though the Properties Panel Icon is already showing the correct path.

I posted the error when I got it, about 20 mins ago but it’s building ok (without any errors) at the moment.