What version of Premiere Elements are you using and on what computer operating system is it running?
What is the Facebook preset that you are using in the Premiere Elements feature Facebook upload?
Are you in a country outside the USA? Have you tried to refresh your Online Services via the Premiere Elements
If you have a AVCHD.mp4 or H.264.mov choice to export your Timeline line, you could always export to file saved to the
computer hard drive and then upload the file from there to Facebook at the Facebook web page.
Please review and consider and then let us know of your progress.