pgadmin3 crash on new server registration / no server instances

Hi,

I wondered if anyone could help me with the following. I have been
trying to view the server instance I have set up by using the pgadmin
GUI. Here it is in the terminal:

postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype |
Access privileges
-----------+------------+----------+-------------+-------------+-----------------------
django_db | django_dev | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
postgres | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
template0 | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
=c/postgres +
| | | | |
postgres=CTc/postgres
template1 | postgres | UTF8 | en_GB.UTF-8 | en_GB.UTF-8 |
=c/postgres +
| | | | |
postgres=CTc/postgres
(4 rows)

But when I run pgadmin3 no server instances are displayed. When I
click on Add server instance I get the below error messages (x8):

(pgadmin3:2587): GLib-GObject-WARNING **: invalid cast from
`GtkFileChooserButton' to `GtkBin'
(pgadmin3:2587): Gtk-CRITICAL **: IA__gtk_widget_modify_style:
assertion `GTK_IS_WIDGET (widget)' failed

I am running Ubuntu on a laptop, and the database is local. The
intended purpose for this database is to store Django app data. Am I
doing something stupid?

Thanks!

Andy