The Edible Napkin

Well this really sucks. I've been working on this project for quite a while now and then I get this out of nowhere. I've read elsewhere of people having this problem. The consensus is "upload your file here so we can look at it, but really there isn't anything we can do." My question is bifurcated. Is there something that I can do? If there is not, then can someone describe to me the .pdn format. If I could just save the first couple layers that would be more than amazing. thanks all.

I will start by saying that I love paint.net. However... Is there is a FULL shortcut list somewhere? I do a lot of repetitive work, lots of cutting, pasting, layer actions, etc. To improve my productivity I used paint.net in conjunction with AutoHotkey. Together they make a great team, however it would be excellent to be even more productive. I have found a couple of shortcuts that aren't in the help file or in the menus (ex. ctrl+direction will move a selection 10 pixels in that direction). Has anyone else found any? Specifically shortcuts for layer visibility, layer selection(move up and down), layer order, and image flipping.