invalid user or password next day in redmine 1.2 with postgresql

OS:debian squeeze(almost all default config)
Redmine:1.2.0 stable
Rails：2.3.11
rake：0.8.7
apache2 with libapache2-mod-passenger
Postgresql 8.4.7

After installed sucessfully, I can log in. But next day Redmine shows me "invalid user or password". Some related info shows below:

1、/var/log/postgresql/postgresql-8.4-main.log
EDT LOG: could not receive data from client: Connection reset by peer
EDT LOG: unexpected EOF on client connection

2、redmine's production.log shows:
Processing AccountController#login (for 192.168.130.75 at 2011-06-16 13:36:32) [POST]
Parameters: {"back_url"=>"http%3A%2F%2F192.168.130.70%2Fproject1", "action"=>"login", "authenticity_token"=>"ZaX0x37DR0V55Tph6xP2N42Zy5TXHHWwb9NfN7oDTNo=", "username"=>"admin", "controller"=>"account", "password"=>"[FILTERED]", "login"=>"ç™»å½• Â»"}
Failed login for 'admin' from 192.168.130.75 at Thu Jun 16 17:36:32 UTC 2011

Best regards

Hugo