Same problem here. Clicking on 'Print Order Page' doesn't do anything. It's worked fine for the last two years and then, from this morning, I can't print it.
I'm sure that there was just a simple 'Print' command at the top of the order page until this morning. This now seems to have been replaced by a drop down menu with 'Print Order Page' and 'Print Packing Slips'
So as of now, I can't print out any orders. I've emailed Support.