Jon,
The preferred method of creating PDF from any of the Microsoft Office products is absolutely not by printing to Adobe PDF. Acrobat installs a PDFMaker capability in Office that shows up as Save as Adobe PDF. That function maintains more of the full fidelity of your Office document since PDF is directly created from those documents as opposed to Word generating Windows GDI commands, the GDI commands converted to PostScript by the PostScript driver, and the PostScript subsequently being converted to PDF by the Distiller running in the background. In the print to Adobe PDF method, Office applications often chop up imported images, especially if the images have a transparent background, since PostScript does not support live transparency. With those chopped up images, you can readily get the symptoms you describe in the resultant PDF file.
- Dov