When Internet Explorer is configured to use Protected Zones, you can not print pages to PDF's using Acrobat's PDF printer. Instead, you'll get an error similar to this one:
D:\Documents\webpage.pdf
You don’t
have permission to save in this location.
Contact the
administrator to obtain permission.
Would you
like to save in the [username] folder instead?
This happens because IE's security won't let the PDF save the file. You have three choices:
Running as Admin turns off the protected zone, even though it remains enabled in Tools, Options. Use this method if you need to print occasionally - start IE with the run as admin option when you need to print to PDF. If you need to print to PDF a lot, turn off protected zones or UAC.