Server shutdowns while browsing in the openerp-web client

I setup a new Installation of OpenERP-Server (Last Version) in a VPS with Ubuntu Hardy 8.04 x64. you can see the openerp-web client visiting http://erp.openit.com.bo/

The installation of openerp-server and the openerp-web client works fine, everython get well without issues.

After a while I get realize that the openerp-server shutdowns very quickly, If I am browsing a lot the webclient it shutdown faster, more faster If I open many views of the modules.

Here is the Log of openerp-server running with the debug option:

root@openit:/usr/lib/python2.5/site-packages/openerp-server# python openerp-server.py --debug --log-level=debug
[2009-07-11 23:00:54,297] INFO:server:version - 5.0.1
[2009-07-11 23:00:54,297] INFO:server:addons_path - /usr/lib/python2.5/site-packages/openerp-server/addons
[2009-07-11 23:00:54,298] INFO:server:database hostname - localhost
[2009-07-11 23:00:54,298] INFO:server:database port - 5432
[2009-07-11 23:00:54,298] INFO:server:database user - openerp
[2009-07-11 23:00:54,298] INFO:objects:initialising distributed objects services
[2009-07-11 23:00:54,498] DEBUG:psycopg2:installed. Logging using Python logging module
[2009-07-11 23:00:54,501] INFO:web-services:starting XML-RPC services, port 8069
[2009-07-11 23:00:54,501] INFO:web-services:starting NET-RPC service, port 8070
[2009-07-11 23:00:54,501] INFO:web-services:the server is running, waiting for connections...
[2009-07-11 23:01:23,264] INFO:dbpool:Connecting to openit
....
[2009-07-11 23:04:50,263] INFO:web-service:successful login from 'admin' using database 'openit'
[2009-07-11 23:06:03,706] ERROR:web-services:[01]: Traceback (most recent call last):
[2009-07-11 23:06:03,706] ERROR:web-services:[02]: File "/usr/lib/python2.5/site-packages/openerp-server/osv/osv.py", line 59, in wrapper
[2009-07-11 23:06:03,706] ERROR:web-services:[03]: return f(self, dbname, *args, **kwargs)
[2009-07-11 23:06:03,706] ERROR:web-services:[04]: File "/usr/lib/python2.5/site-packages/openerp-server/osv/osv.py", line 125, in execute
[2009-07-11 23:06:03,707] ERROR:web-services:[05]: cr.close()
[2009-07-11 23:06:03,707] ERROR:web-services:[06]: File "/usr/lib/python2.5/site-packages/openerp-server/sql_db.py", line 76, in wrapper
[2009-07-11 23:06:03,707] ERROR:web-services:[07]: return f(self, *args, **kwargs)
[2009-07-11 23:06:03,707] ERROR:web-services:[08]: File "/usr/lib/python2.5/site-packages/openerp-server/sql_db.py", line 162, in close
[2009-07-11 23:06:03,708] ERROR:web-services:[09]: self.rollback() # Ensure we close the current transaction.
[2009-07-11 23:06:03,708] ERROR:web-services:[10]: MemoryError
[2009-07-11 23:06:02,821] INFO:shutdown:Shutdown Server! - SIGTERM

The python Exceptions, are not always show. Most of the time I just get the "Shutdown Server! - SIGTERM" signal.

Here is my configuration file for openerp-server:

root@openit:~# cat /etc/openerp-server.conf
# /etc/openerp-server.conf(5) - configuration file for openerp-server(1)
[options]
verbose = True
pidfile = /var/run/openerp.pid
logfile = /var/log/openerp.log
interface =
port = 8069
debug_mode = True
secure = False
smtp_server = localhost
smtp_user = False
smtp_password = False
db_name =
db_user = openerp
db_password = *****************
db_host = localhost
db_port = 5432
assert_exit_level = 30

I am quite worried, as I can not understand why the openerp-server is shutting down every time I am using the openerp-web client.

Running both openerp-server and openerp-web client I have 70MB of free ram, and the cpu doesn't get stalled.

Any hints how to solve this issue?