That's not just it. "W: Conflicting distribution: http://repository.maemo.org fremantle-1.2 Release (expected fremantle-1.2 but got )" is an entirely different error. I've had it crop up before. As near as I can tell, the best solution is to just re-enter your repositories in the N900's app manager. I'm stuff unsure what causes it, but I've only gotten it once or twice since I started using FApMan instead of the stock App Manager. And while with HAM it tended to be a show stopper every once in a while, with FApMan it never seemed to cause problems installing things.

*Shrug* But yes, the other errors should be resolvable by just making sure you're running apt-get as root, and don't have another package manager open (since package managers are just UI front-ends for apt-get anyway).