In Mac OS X 10.6.7, Apple introduced a bug where if you have a document containing OpenType fonts, and used the OS X PDF engine to generate a PDF, you could have trouble opening it in Adobe Acrobat or printing it to to a PostScript printer. Apple has now addressed the problem through the Snow Leopard Font Update.
This bug may seem obscure to some, but OpenType is a high-quality cross-platform font standard that professional designers rely on, so it was messing up some workflows. Also, OpenType fonts are bundled with some Adobe Creative Suite applications, so you may have those fonts on your computer even if you don’t remember installing them.
Download Snow Leopard Font Update