OK, so when you have the problem you are out-of-the-office and you connect to one of 2 in-office computers using a VPN connection. From your description, Adagio is installed on those 2 computers, not on the computer you are using when out-of-the-office (that was Doug's main concern - some people want Adagio installed on their home computer and then use a VPN to access the data on their office server and that configuration will usually lead to damaged data ... at some point).

-Where are you saving the PDF file - on your out-of-the-office computer or on one of the 2 in-office computers?
-Presumably when you are in the office using one of those 2 computers, you don't have the same problem with invoices in PDF format?