XPrmDir()
   Remove a DOS directory
------------------------------------------------------------------------------

   Function:   XPrmDir()

               Use XPrmDir() to remove directories. The directory
               must be empty and Not be the DOS current directory.

   Syntax:     XPrmDir(<cDir>) --> nError

   Arguments:  <cDir> is the name of the directory to remove.

   Returns:    A numerical value, 0 meaning No error, others
               values indicate an error, the number is the DOS
               error code (eg. 5=Acces denied, 17=Attempt to remove
               current directory).

   Usage:      XPrmDir('DATA\OLD')