i;ve got the same problem but on n900
after installing some apps i got error not enough memory in target location and couldn't install anything
so rebooted
after that app manager stopped showing any apps installed
here's log:
hildon-application manager 2.2.35-3
write:broken pipe
write:broken pipe
apt-worker exited
apt-worker: can't truncate lock /var/lib/hildon-application-manager/apt-worker-lock: no space left on device

and cannot uninstall anything
i understand that somehow app manager installed the apps on root and filled it up - guessing only (i'm a windows user)

tried deleting folders and files but nothing works
downloading flash file..

still hesitate to use wnd solution - in case breaking something further

any help greatly appreciated