China DOS Union

I have an optical disc image file named 5.img, about 4.3M, which may work normally in the optical drive. Now I put it in the boot\grub folder of the C drive and use grub to boot it. But after adding the following code in menu.lst to boot, an error is prompted. Where did I go wrong and how to correct it? Please give more guidance from the experts.

title Chinese Boot Disk
map --mem /boot/grub/5.img (fd0)
map --hook
chainloader (fd0)+1
rootnoverify (fd0)

Error content prompted
error 1: filename must be either an absolute pathname or blocklist
press any key to continue......

The path is incorrect.
map --mem (hd0,0)/boot/grub/5.img (fd0)

Grammar error, as for whether it is (hd0,0), it depends on the partition situation of your computer. Generally, C:\ is (hd0,0).

The file is on the C drive, but changing it to the following still prompts the same error
map --mem (hd0,0)/boot/grub/5.img (fd0)

The GRUB version you are using is too old and does not support the --mem parameter.

I changed to 0.42 and it still doesn't work. I don't know where the problem is.

Low-level error: There is a missing space between --mem and /boot/grub/5.img. Or the file does not exist, or the file path is miswritten.