resolution problem

I need your help. I ported android to beagleboard (embinux cupcake).
And I connected with a picoprojector. projector resolution is
848x480@60. I have a problem at projector resolution. I uploaded a
photo to group files section (SNC00066.jpg). Please can you look it.
My boot setup:
setenv bootargs console=ttyS2,115200n8 noinitrd root=/dev/mmcblk0p2
video=omapfb.mode=dvi:848x480@60 init=/init rootfstype=ext3 rw
rootdelay=1 nohz=off androidboot.console=ttyS2

how can i solve this? Thanks,
(sorry for my English)