Whoa, I didn't expect that file size. Well, there's something clearly wrong, because the ROM I've got (which patches normally) is 3.00 MB.
I can only guess you've got a prepatched, maybe Chinese, ROM.
You'll probably have to obtain a ROM from a different location and then check to see if the file size matches.
I guess planetemu.net is not a good place to look. ^^; Where do you suggest I look?