Are you sure the font is actually installed on your system? Look in
\windows\fonts for it. Some fonts are "printer resident." These are fonts
that are hardwired inside your desktop printer. The printer driver tells
Windows how to display these fonts on screen-- and, since the fonts are
hardwired inside your desktop printer, the desktop printer can print them,
too. But the fonts are not actually installed on your computer, so they
cannot be embedded in a PDF and that forces Acrobat/Distiller to substitute.
Most printer manufacturers also include their printer-resident fonts on
disk, so that you can truly install them. However, that installation isn't
part of the printer setup. You have to manually look for the fonts on the
installation CD and then manually install them.