编译显示“invalid character in file”,求帮助啊，在线等解答

DATAS SEGMENT
stringdb ’Hello,Everybody !’0AH,0DH,’$’
DATAS ENDS
STACKS SEGMENT
dw 512 dup(?) ;堆栈段有512字（1024字节）空间
STACKS ENDS
CODES SEGMENT
ASSUME CS:CODES,DS:DATAS,SS:STACKS
START:
MOV AX,DATAS
MOV DS,AX
mov dx,offset string
mov ah,9
int 21h
MOV AH,4CH
INT 21H
CODES ENDS
END START