The GLKTextureLoader I'm using since Sparrow 2.0 is really the crappiest API I've ever seen. 90% of all errors I had with Sparrow 2.0 are because of this class.
In this case, the error you get is the following:
Could not find resource my-file.png at specified location.
But it's there -- iOS 5 and iOS 7 simulators find it, and all real iOS's.
🤬 🤬 🤬
All I can do is add a warning telling you that it's just a simulator bug.