If you use qemu you need to pad your image to a integer multiple of the size of a sector.
Add this at the end of image.asm:
times 512*2-($-$$) db 0
And assemble and run with:
nasm -f bin -o image.bin image.asm
qemu-system-i386 -fda image.bin
With another emulator you might have to pad to a total length of (1+5)*512 or even to the full length of a floppy (1474560 bytes).