i recently flashed my n900 and now i cant find certain apps in the repos and cant install certain apps from xterm?

for example i tried reinstalling preenv and nitdroid-installer via xterm with:
root apt-get install preenv
or
root apt-get install nitdroid-installer
and i'm getting 'packages not found'

and in the repos i cant find certain apps that was there before e.g 'unzip and unrar addon for file manager'

these were all the apps i had installed previous before flashing

anyone had this before or know of a solution?
any help appreciated