Places a hyperlink at the given position pointing to a file program
which is being started when clicked on. The hyperlink start is
a rectangle with its lower left corner at (llx, lly) and its upper right
corner at (urx, ury). The rectangle has by default a thin blue border.
The hyperlink will not be visible if the document is printed or
viewed but it will show up if the document is converted to pdf by either
Acrobat Distiller™ or Ghostview.