I'm sorry for the trouble you're having, and I don't doubt there's some issue at play, but it doesn't appear to be with the plugin. There will either be a viewer or an error in every circumstance unless something else is interfering.
I was able to borrow an iPad (2) for a moment and snapped a photo of the document in question appearing just fine on it:
If you haven't cleared your browser cache already, that's a good thing to try in cases like these where you're having local issues. The other possibility is that browser settings or plugins are blocking iframe support, or the docs.google.com domain, or something to that effect.
Wish I could be more help, but what you're describing isn't behavior from my plugin, and it does appear to "just work" from here on the link you've provided.