Your repositories are not correctly set up/up to date if it can't find hildon-desktop. What do you get from running "apt-get update"?
home/user # apt-get update Get:1 http://repository.maemo.org fremantle-1.3 Release.gpg [489B] Ign http://repository.maemo.org fremantle-1.3/free Translation-en_GB Ign http://repository.maemo.org fremantle-1.3/non-free Translation-en_GB Hit https://downloads.maemo.nokia.com ./ Release.gpg Ign https://downloads.maemo.nokia.com ./ Translation-en_GB Ign http://static.bambuser.com ./ Release.gpg Ign http://static.bambuser.com ./ Translation-en_GB Hit http://repository.maemo.org fremantle Release.gpg Ign http://repository.maemo.org fremantle/free Translation-en_GB Ign http://repository.maemo.org fremantle/non-free Translation-en_GB Get:2 http://repository.maemo.org fremantle Release.gpg [489B] Ign http://repository.maemo.org fremantle/free Translation-en_GB Ign http://repository.maemo.org fremantle/non-free Translation-en_GB Get:3 http://repository.maemo.org fremantle Release.gpg [489B] Ign http://repository.maemo.org fremantle/free Translation-en_GB Ign http://repository.maemo.org fremantle/non-free Translation-en_GB Ign http://moff.mozilla.com chinook Release.gpg Ign http://moff.mozilla.com chinook/release Translation-en_GB Hit https://downloads.maemo.nokia.com ./ Release.gpg Ign https://downloads.maemo.nokia.com ./ Translation-en_GB Get:4 https://downloads.maemo.nokia.com ./ Release.gpg [198B] Ign https://downloads.maemo.nokia.com ./ Translation-en_GB Ign http://my-maemo.com fremantle Release.gpg Ign http://my-maemo.com fremantle/user Translation-en_GB Hit https://downloads.maemo.nokia.com ./ Release Hit https://downloads.maemo.nokia.com ./ Release Get:5 https://downloads.maemo.nokia.com ./ Release [507B] Ign http://repository.sygic.com fremantle Release.gpg Ign http://repository.sygic.com fremantle/non-free Translation-en_GB Get:6 http://repository.maemo.org fremantle Release.gpg [489B] Ign http://repository.maemo.org fremantle/free Translation-en_GB Ign http://repository.maemo.org fremantle/non-free Translation-en_GB Get:7 http://repository.maemo.org fremantle-1.3 Release [7956B] Ign http://static.bambuser.com ./ Release Ign https://downloads.maemo.nokia.com ./ Packages/DiffIndex Hit http://repository.maemo.org fremantle Release Get:8 http://repository.maemo.org fremantle Release [7958B] Get:9 http://repository.maemo.org fremantle Release [7955B] Ign http://moff.mozilla.com chinook Release Ign https://downloads.maemo.nokia.com ./ Packages/DiffIndex Ign http://my-maemo.com fremantle Release Ign http://repository.sygic.com fremantle Release Get:10 http://repository.maemo.org fremantle Release [7952B] Ign http://repository.maemo.org fremantle-1.3/free Packages/DiffIndex Ign http://repository.maemo.org fremantle-1.3/non-free Packages/DiffIndex Ign https://downloads.maemo.nokia.com ./ Packages/DiffIndex Ign http://static.bambuser.com ./ Packages/DiffIndex Ign http://repository.maemo.org fremantle/free Packages/DiffIndex Ign http://repository.maemo.org fremantle/non-free Packages/DiffIndex Ign http://repository.maemo.org fremantle/free Packages/DiffIndex Ign http://repository.maemo.org fremantle/non-free Packages/DiffIndex Ign http://repository.maemo.org fremantle/free Packages/DiffIndex Ign http://repository.maemo.org fremantle/non-free Packages/DiffIndex Ign http://moff.mozilla.com chinook/release Packages/DiffIndex Hit https://downloads.maemo.nokia.com ./ Packages Hit https://downloads.maemo.nokia.com ./ Packages Ign http://my-maemo.com fremantle/user Packages/DiffIndex Get:11 https://downloads.maemo.nokia.com ./ Packages [763kB] Ign http://repository.sygic.com fremantle/non-free Packages/DiffIndex Get:12 http://repository.maemo.org fremantle-1.3/free Packages [2449kB] Get:13 http://repository.maemo.org fremantle-1.3/non-free Packages [67,6kB] Ign http://repository.maemo.org fremantle/free Packages/DiffIndex Ign http://repository.maemo.org fremantle/non-free Packages/DiffIndex Get:14 http://static.bambuser.com ./ Packages [2556B] Hit http://repository.maemo.org fremantle/free Packages Hit http://repository.maemo.org fremantle/non-free Packages Get:15 http://repository.maemo.org fremantle/free Packages [7188kB] Get:16 http://repository.maemo.org fremantle/free Packages [7188kB] Get:17 http://repository.maemo.org fremantle/non-free Packages [218kB] Get:18 http://repository.maemo.org fremantle/free Packages [3286kB] Get:19 http://repository.maemo.org fremantle/non-free Packages [92,7kB] Ign http://moff.mozilla.com chinook/release Packages Ign http://my-maemo.com fremantle/user Packages Hit http://repository.sygic.com fremantle/non-free Packages Get:20 http://repository.maemo.org fremantle/free Packages [2309kB] Get:21 http://repository.maemo.org fremantle/non-free Packages [67,6kB] Err http://moff.mozilla.com chinook/release Packages 404 Not Found [IP: 63.245.208.197 80] Hit http://my-maemo.com fremantle/user Packages Fetched 15,3MB in 4min15s (59,7kB/s) W: Failed to fetch http://moff.mozilla.com/latest/maemo...armel/Packages 404 Not Found [IP: 63.245.208.197 80] E: Some index files failed to download, they have been ignored, or old ones used instead.