Loosing connection with the database

Hi,

I'm experiencing some strange problems with a Java application which I
have made.
Suddently it looses connection with the database, and in the server log
i can find:

2005-04-02 00:09:01 ERROR: invalid string enlargement request size
1358954492
2005-04-02 00:09:01 WARNING: AbortTransaction and not in in-progress
state
2005-04-02 00:09:01 FATAL: invalid frontend message type 82

2005-04-02 07:36:24 ERROR: invalid string enlargement request size
1358954492
2005-04-02 07:36:24 WARNING: AbortTransaction and not in in-progress
state
2005-04-02 07:36:24 FATAL: invalid frontend message type 78

2005-04-02 12:03:08 ERROR: invalid string enlargement request size
1358954492
2005-04-02 12:03:08 WARNING: AbortTransaction and not in in-progress
state
2005-04-02 12:03:08 FATAL: invalid frontend message type 78

Sometimes it can run for days without any problems, but now it has died
3 times today.
The server is running SuSE Linux 9.2, the Postgresql version is 7.4.7
I have tried two different version of the jdbc driver pg74.215.jdbc3.jar
and pg80.310.jdbc3.jar
but it's the same result.

Can anyone tell me what's causing this, please ?

BR, Poul