I have no idea what has happened. My N800 (OS2008) Application Manager has gone stupid. I tried to display the list of available applications and it failed. Then I looked at the Application Catalogs screen, and it was empty! I tried adding a repository by hand, and when I clicked the OK button it disappeared.
Then I looked at the list of INSTALLED applications, and it too was empty!
I'm guessing that I need to re-install Application Manager, but I don't know enough about how to do it.
I tried various apt-get commands (as root) and got error messages that it could not lock /var/lib/dpkg/lock because of no space left on device.

So, how can I get out of this mess? I can't use Application Manager or apt-get to remove any applications. My documents and so on are already on SD cards. I'm very uneasy about just arbitrarily deleting files.

Help, Please

Walt