INT 21 - Novell NetWare - WORKSTATION - SET NetWare ERROR MODE                  
	AH = DDh
	DL = error mode
	    00h invoke INT 24 on critical I/O errors (default)
	    01h return NetWare extended error code in AL
	    02h return error code in AL, mapped to standard DOS error codes
Return: AL = previous error mode
Note:	this function is supported by Advanced NetWare 2.0+
SeeAlso: INT 24