Hi!

Do you have any watchdog that does something with the network (i.e., to 
monitorize de interface status, etc...)?

I have been found the same problem with Debian Sarge + PgSQL 8.0.3 and I 
have
been correct by simply disabling a watchdog that monitorizes the network 
interface.

I hope this will help you...
Bye,
Joxean Koret