HELP!!!

Hi,

I am using a Live PostgreSQL database system for multiple web applications.
Everything was all working fine until completely at random the database
engine came up with a JDBC error:
"The backend has broken the connection. Possibly the action you have
attempted has caused it to close."

Now every time i attempt an UPDATE on the database it comes back with the
same error.
I can still do SELECT statements on the database with no problems.

The software i am using:
PostgreSQL 7.2.2
Java 1.4
Red Hat Linux 7.2

I have tried restarting the JVM
I have tried restarting PostgreSQL
I have tried rebooting the machine completely

The same error keeps occuring.

Please Help,

-- Brendon