If you don't have any details of living people in it, andsend it to me as an attachment, I'll try to import it into Roots Magic. If RM gets an error, I will send you the error. If not, I'll send you a GEDCOM generated from your data by Roots Magic, which Ancestry may like better.
I'm assuming that whatever glitch PAF put into it is a glitch PAF knows and loves, so importing it back into a temporary PAF data base would not reveal the problem. You could import it into any non-PAF program as a test, but I happen to use RM.
When I import a GEDCOM into Roots Magic, I get a log file named ffff.LST, where "ffff" is the name of the GEDCOM file; smith.LST, test.LST, etc. If you get a .LST file when you upload to Ancestty, it may give you a clue.