problem with databases

I'm trying to get IMP to work, and I need to create 2 databases which I have
problems creating.
What I get is this:

GRANT SELECT, INSERT, UPDATE ON active_sessions, auth_user, auth_user_md5 TO nobody;
ERROR:  aclparse: non-existent user "nobody" 

I don't know how to add the user nobody to grant him with permission to
connect to the horde database.

TIA!

-- 
"And I'm happy, because you make me feel good, about me." - Melvin Udall
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Mart�n Marqu�s			email: 	martin@math.unl.edu.ar
Santa Fe - Argentina		http://math.unl.edu.ar/~martin/
Administrador de sistemas en math.unl.edu.ar
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