Failed to open connection to session message bus

Whenever I run an application such as Epiphany (which is barely running, but enough for me to do this), I get the following error message:

Failed to open connection to session message bus: Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.

I have done a 'ps ax | grep dbus' with the following results:

10145 ? Ss 0:00 /usr/bin/dbus-daemon --system
10885 ? S 0:00 /usr/bin/dbus-launch --exit-with-session /usr/bin/seahorse-agent --execute /usr/bin/gnome-session
10886 ? Ss 0:00 /usr/bin/dbus-daemon --fork --print-pid 6 --print-address 9 --session
11178 pts/3 S+ 0:00 grep dbus

As far as I can tell, the session message bus is running. So, I checked into the security policy by having a look at the session.conf file in /etc/dbus-1 - and understood very little with the file contents being a per the attached file.

I have now exhausted my limited knowledge in this area. So, can someone please help so that I can get things running properly again ?

Thanking you,
Brett Senior.