Your first wrote:
My problem is that when I export the completed document to a pdf, the text in a couple of text boxes doesn't show up in the pdf.
You then wrote:
I still can't see the text when I print the same file to a pdf on my own MacBook, as well as on a PC.
So your type on the display is the same in Apple Preview on Mac OS X and Adobe Reader on Microsoft Windows, but your type on the printer is not the same from Apple Preview on Mac OS X and Adobe Reader on Microsoft Windows?
If it's a printing problem and not a display problem, you might try setting Adobe Reader to "Print as Image". With this setting the PDF is RIP'ed to a colour picture element pattern by Acrobat Reader before the data is downloaded through the system to the printer.
This should sort glyph substitution problems, transparency problems and more in advance. I hope -:).
/hh