Soon is tough and often requires files to be expedient.
What font(s) and what type of fonts are they?
On a non-printing layer?
Extreme possibility would be to reset QXP deleting you preferences with QXP shut down and restarting, load the project and immediately try the export to pdf again.
If you would like, please collect for output, ZIP that folder structure up, upload the ZIP to dropbox or the like and if not needing to be kept private, provide a download link in a response. Else feel free to PM me the download link.