how to build yaffs2 rootfs for mini6410

Eng Halim
hello all 
i have mini6410 and want to build my own embedded linux OS so i cross
compiled kernel and boot loader and it worked very good but when i compile
busy box and make rootfs.img and begin to install the sys i have this
problem on my screen 
Bad Yaffs image file 

So what is the error ? 
and how can build my rootfs with correct way and how to include my GUI that
will build with Qt into it ?

and thanx for caring :)

Legath
just you need mkyaffsimage tool
http://code.google.com/p/yaffs2utils/