Android emulator cannot be started from windows console

I'm trying to run my android emulator on windows console but I get this error:

emulator: ERROR: Your system directory is missing the 'kernel-qemu' image file.
Please specify one with the '-kernel <filepath>' option

how can I fix this?. thanks for tour time.

----- UPDATE -----

I finally can fix this error. At fisrt, I planned to install android SDK offline rather than using SDK Manager. So I followed up this instruction and downloaded the components I need. Everything is correctly except that when开发者_如何学JAVA I extract the platform using IZArc the file kernel-qemu which located in /platform/images/ is not extracted. But when I manually choose the file from IZArc and drag it to any folder it's extracted. Maybe this is about IZArc configuration but this error cost me for almost a week!

do you have your kernel image file under

< android >/tools/lib/images/

directory?

but i think your problem is your sintaxis to run the emulator

./emulator -kernel kernel-qemu -system system.img -ramdisk ramdisk.img -initdata userdata.img -partition-size 512