Thanks, Pat. There are a number of options in PAF 5 for creating GEDCOM files. I am just wondering if perhaps your relatives, inadvertently, had the option set to something other than PAF 5. This could be the cause of your problem.
The other area to look at is, has your PAF 5 been running error-free since installing? Sometimes errors in running crop up particularly if PAF 5 has not been installed strictly in accordance with Windows install procedures: closing down all running programs except Explorer and Systray, and going through START|SETTINGS|CONTROL PANEL|ADD/REMOVE PROGRAMS to complete the install. Many times PAF will run ok, even if installed incorrectly, but then it will suddenly fail to do something when attempting a new step. Have you been able to import other GEDCOM files previously without any bother? If you have, then it may point back to the way this one was created (as above).