After a bit of searching, I found this, which says
After hours of tinkering around trying to save/export an OpenOffice file to a PDF format, I found a simple yet crude solution. Go to the Abobe Reader included with the free Adobe software, and open it. On the right-hand side, it will give you the option to save as a PDF. Insert the name/location of the file (copy and paste it into the spot offered), and voila, it is converted and saved!!
and this, which suggests going to File > Export in OpenOffice.
Try something like PDFCreator, it acts like a printer as far as any software on windows is concerned, there may be others out there but that’s the only one that I’ve ever used and to date it has worked fine for me.