Format of DOS 4.x error table:
Offset	Size	Description	)
 00h	BYTE	FFh
 01h  2 BYTEs	04h,00h (DOS version???)
 03h	BYTE	number of error headers following
 04h 2N WORDs	table of all error headers for table
		Offset	Size	Description
		 00h	WORD	error message number
		 02h	WORD	offset of error message from start of header
				error messages are count byte followed by msg
Note:	DOS 5 error tables consist of one word per error number; each word
	  contains either the offset of a counted string or 0000h