The viewer looks really good. A few comments: (I hope that they're useful).
1. I don't understand the usefulness of the current implementation of the document 'rotation'. it would be more useful to rotate the document along the document's center. Right now it rotates with the upper left-hand corner as the document center. There should also be buttons for the rotation up on the toolbar.
2. When the mouse if hovering over the regular document, it should be the open-hand cursor. The pointed-finger cursor should indicate something that can be clicked on.
3. left-clicking on the document currently scrolls the page down. I don't think that clicking should do anything.
4. customize the right-click options so that you remove the flash-specific ones and only put in ones that are usefull for the document "previous page" "next page" etc.