problem apt

[mickael <debian (at) robertain.com>]

Hi , 

I'm new user hobbit and i must migrate our solution monitoring nagios to hobbit . I test hobbit from VM with a client and a server. I have some problems : 
first : i obtain this message : 
Packages not installed from apt repositories:
  postfixadmin (2.3)

How to edit hobbit no longer have this error ? 

Second problem i obtain this error : 
No entries in /var/log/messages <http://serveur/hobbit-cgi/bb-hostsvc.sh?CLIENT=Serveur.robertain.com&SECTION=msgs:/var/log/messages>
Full log /var/log/messages <http://serveur/hobbit-cgi/bb-hostsvc.sh?CLIENT=Serveur.robertain.com&SECTION=msgs:/var/log/messages>
Cannot open logfile /var/log/messages : Permission denied

What user hobbit use for open a file on the system ? 
Thank you for your help 

Best Regards , 
Mickael