Cross-browser compatible display of PDF's is a pretty tough nut to crack :(
Although not ideal for all situations, using a 3rd party company that will convert the PDF for display is a good work-around.
I've used Scribd with reasonable success. You upload docs to your (free) account on the Scribd site, they convert your Docs to a format that you can display on your site with an Html block.
The marketplace has an add-on for this but its pretty easy to set up yourself.
You are allowed to delete your post for 5 minutes after it's posted.