rootfs on Tiny4412problem

system282
Hi
I wanna put rootfs on a tiny4412 .I made a rootfs with this instruction:
make_ext4fs -s  -l 314572800  -a root  -L linux rootfs_qtopia_qt4.img 
rootfs_qtopia_qt4
and now I see this error when my board is booting:

switch root : bad init /linuxrc:permission denied
...
would you help me how can I correct it ,pleass?