Function:   PrintError()

               When PRINT is installed and there are some files
               to be printed, this function returns the number of
               printer Errors PRINT encountered when trying to
               output the last character.

               A call to this function freezes the printing of
               files. When a possible error situation has been
               resolved, restart printing with PrintResume().

   Syntax:     PrintError() --> nErrors

   Arguments:  None

   Returns:    A number indicating the number of errors that
               occured when trying to output the last character.
               Any positive number thus indicates errors on list
               device.

   Usage:      Use this function from time to time, just to check
               if the List device is still accepting characters.
               Don't forget to restart using PrintResume().