That may be the solution.

If Synaptic can't run (or the equivalent updater due to lack of disk
space), you're running behind current updates for 8.04.1 (LTS).

Partitioning recommendations from "others" has been a problem with both
UNIX and Linux since the 1990s. With today's hard disk capacities and
assuming the system is a personal workstation, there's no reason to
partition a disk into separate slices for /, /var, /usr, etc. Even with
my Solaris systems everything (except swap) is in a single partition
under / with the exception for a separate partition for a "live update".

/home may be an exception -- this depends on one's requrements.