INT 7D - SCSILink - GET ERROR STRING                                            
	AH = 04h
	AL = error number
Return: ES:BX -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. error string for error number