instead of saving as a PDF I suggest printing the document to the distiller. This will open up a file dialog box that will allow you to enter the PDF file name.
I've had problem in the past with the "speed buttons" and "save-as" options. I've had great results using the distiller.
If you don't already know, you can select Acrobat (or Acrobat Distiller [depending on you system]) from the "File->Print" menu options.
good luck.
Aloha,
cg