I had that problem with my brothers n900 as well. i updated mine to PR1.3 befor his, i was able to restore all my programs fine but when i did his i was unable to install swappolube. missing python-qt4-common dependency. i tried installin the dependency manually with apt-get but the version it installed appeared to be a updated package 4.7.5. eventually i just gave up and installed swappolube no gui instead