Segment reference in NASM

[abdul]

I am using NASM now instead of TASM but the syntax is pretty different. I am trying to a usual "Hello World" program but it gives me an error when I try to get the segment of a variable or symbol (although NASM supports that).
Here's the code:

bits 32
section.data:
message db "Hello", "$"
section.text:
_start:
mov ax, seg message
mov ds, ax
mov dx, message
mov ah, 9h
int 21h

mov ax, 4c00h
int 21h 

It gives me this error:

a.asm:6: error: binary output format does not support segment base references

Line 6 is mov ax, seg message