HELP: I'm trying to install navit (SVN 3582)but my N900 tells me an application package libgpsbt is missing. Can somebody tell me where and how to get it?

I have tried <apt-get install libgpsbt > in X terminal but my N900 tells me "E: could not open lock file /var/lib/dpkg/lock - open (13 permission denied)" and "E: Unable to loch the administration directory (/var/lib/dpk/), are you root?"

Please tell me what to do now...