I have a problem with a few of my pdfs. They are not always fully loading in the browser (sometimes they do, but more often they don't). They get stuck at various points and quit loading. The one i have been experimenting with is 2.01 MB, so I don't think size is an issue. It doesn't matter what browser, FF, IE, Chrome, it just gets to a certain point and then stops. Sometimes it will even crash the browser. Created in Acrobat and compressed to reader 8 and above, if that makes any difference.
My first post here... if there is a way to privately send a message, I can send a link to the pdf that I have been experimenting with.
Maybe it's the toolbar conflict, if possible try to uninstall them as a try !