We hear about this every now and then but have been unable to overcome the problem. For some reason the file downloads but then cannot be found by the Acrobat software on your computer.
The solution is to save the file to your computer and then open it and print.
When you click on the Print tab, a dialog box will appear giving you the option to either Open or Save the file. Choose Save and select a location on your computer. The file will begin downloading. When it has finished, find the file on your computer and double click it to open it. It should now open in Acrobat as expected and you can print it through File, Print.
We're not quite sure why this sometimes happens, although we have noticed that it does happen when Acrobat Pro is installed rather than just the standard Acrobat Reader. If anyone has any further ideas, please get in touch.