File Conversion Error with Word.docx

I've not had this problem before when creating a pdf from a Word doc (or converting a Word doc to pdf) but now, all of the sudden when I need to get this out to my client, I cannot get the Word docx to convert to PDF.  I'm doing this so I can combine the darn file with another pdf document because when I try to combine multiple files, this Word docx says there is a conversion error.  Will someone help quickly please?  I need to get this out within the hour.