If you have Acrobat Pro 9.0 installed on OSX 10.6 Snow Leopard, you will not be able to use the Adobe PDF Virtual Printer. When you print to it, it'll look like its all working, but no PDF will be created, and in the logs you'll see
sandboxd DistillerIntf(2544) deny file-write-data /Users/steve.jobs/Library/Application Support/Adobe/Acrobat/Distiller 9/Messages.log
There is no workaround. You need to update Acrobat to 9.1 and this will remove the virtual printer, replacing it with "save as Adobe PDF".
I found that this would crash on me with 9.1, so carry on updating to 9.3.1 (current).
Get your Acrobat updates from www.adobe.com/support/downloads/product.jsp?product=1&platform=Macintosh, but make sure you've got good broadband since getting from 9.0 to 9.3.1 takes 435Mb!