hi...need urgent help pls!!

hi,please help. i tried downloading nitdroid from the application manager but it didnt show up in extras devel..and i couldnt get it by apt get...someone suggested adding a repo of nitdroid..that didnt work too...so i tried downloading nitdroid-installer_0.2.7_armel.deb from nitdroid downloads...it gave an error about 2 missing dependencies...multiboot-kernel-maemo_0.3_armel.deb and multiboot_0.2.10_armel.deb. i tried downloading and installing them directly. i installed multiboot_0.2.10_armel.deb, got a msg to update..and did so. now when i start my phone...i get a white screen with the msg 'press a key to select' it has nokia n900 multiboot written on top and the number 30 on the right.i have tried pressing all the keys but nothing happens, expect that the numbers count down to 1 and start on 30 again.the phone switches off after some time automatically...any help...whats happening?