We require a lot more information than you have provided here. Please refer to the following and update your bug report.

http://docs.kali.org/troubleshooting/submitting-issues-kali-bug-tracker

I had the some thing happen last Thursday when the new Metasploit package was pushed out.
This should fix your issue:
www.offensive-security.com/metasploit-unleashed/Using_the_Database

In Kali, you will need to start up the postgresql server before using the database.
root@kali:~# service postgresql start
[ ok ] Starting PostgreSQL 9.1 database server: main.

Once you start the metasploit service it will create a msf3 datauser user and database called msf3.

root@kali:~# service metasploit start
Configuring Metasploit...
Creating metasploit database user 'msf3'...
Creating metasploit database 'msf3'...
insserv: warning: current start runlevel(s) (empty) of script metasploit' overrides LSB defaults (2 3 4 5). insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of scriptmetasploit' overrides LSB defaults (0 1 6).
[ ok ] Starting Metasploit rpc server: prosvc.
[ ok ] Starting Metasploit web server: thin.
[ ok ] Starting Metasploit worker: worker.

Closed.