Crash: backup / restore

PGAdmin hangs when dumping / restoring a database. I can get to the
screen that has the pg_dump / pg_restore command, but after that screen
is displayed there is no progress, and only thing I can do is kill the
program. (the file dumped to is created but it is empty).

I thing the bug is related to my pg_hba.conf, relevant lines:

local all all trust
host all all 127.0.0.1/32 trust
host all all xxx.zzz.0.0/16 md5

I use user "akaariai" which has no password and which is both database
superuser and my local linux user.

My PGAdmin connection is set up as follows:
name: localhost
host: localhost
port: 5432
maintenance_db: postgres
username: akaariai
store password checked, restore_env checked. Nothing else set, that
means also no password set. I can open the connection without any errors.

The command PGAdmin is trying to run when backup is requested:
pg_dump --host localhost --port 5432 --username akaariai --format ...

If I run the command manually, the command asks for password. If I run
the command without "--host localhost", there is no password prompt.
Could it be that PGAdmin doesn't expect the server to ask password?

Also, if I remove the host=localhost from pgadmin connection
configuration (leaving host blank), I can backup any DB without errors.

I am using ubuntu 10.04, apt installed postgresql 8.4.5, apt installed
pgAdmin, version: 1.10.2 rev 8217.

- Anssi