Thank you for the update. What I have done for the past several months is to save my main PAF file (and the folder of linked media files) to a free DropBox.com account. One of my computers runs XP, one runs Vista and one runs Windows7. My Dropbox account is installed on all of them.
Since I am saving my PAF data in the Dropbox folder on any of my computers I can run PAF on Windows7 just like I have on earlier versions of Windows. I back up my PAF data to ZIP files on the individual computers (whichever one I am on when I get the "Please backup ..." message).
Dropbox automatically synchs my data across my different computers, so I can edit data on any of them and it gets updated on the others the next time they connect with the internet.
PAF remembers the location of the data file you are using, so you only need to save it to a Dropbox folder once, and it should open in the Dropbox folder on that computer from then on. On a different computer, you will need to browse to your Dropbox folder the first time you open that file. Subsequently, it should automatically open the copy of that data file on that computer too.
DISCLAIMER: I have no connection to Dropbox.com beyond being a subcriber to their free 2GB account.