Thank you for your post.
Using FileMaker Pro 10.0v3 and FileMaker Pro 10.0v3 Advanced, on both Windows Vista and Windows XP SP3, I could not replicate the problem. This is what I did:
1. I opened an existing database file and added a text block to a footer.
2. For font, I did not have Lucida Sans showing, so I added it.
3. I changed the font size to 6 pt.
4. I pulled down the File menu and selected "Save/Send Records As -> PDF...".
5. I let the file name default to Untitled.pdf and saved it.
6. I opened Untitled.pdf, and the text block with Lucida Sans appears in the footer on each page.
It is possible there is a problem with the layout itself. Try creating a new layout with minimal fields, and enter a text block in the footer. Save/Send Records As PDF, and see if the PDF contains the footer. If so, then remove the Text block from the original layout, and recreate it. Does this work?
Any additional information you can provide may be helpful in narrowing down the possible cause(s).