problem in calling bios routines in masm

;bios routine direct calling

page 100,100
title 'bios routine'

.model small

.stack 64

.data

.code
main proc far
	mov ax,@data
	mov ds,ax
	mov es,ax
	
	
	; calling bios routine to show a charaacter on the screen
	
	mov ah, 0x0e
	mov al, '!'
	int 0x10
	

	;return to o.s
	mov ax,4c00h
	int 21h
	
	main endp
end main

bios.asm(21) :error A2206 : missing operator in expression
bios.asm(23) :error A2206 : missing operator in expression