[ossec-list] Ossec server cannot detect agent`s OS and client versions

[Roman]

Hi,
I have OSSEC server on RHEL 5.6 (Tikanga) 32 bit. Clients are mix of
Windows 2003 Server, RHEL 5.6, HP-UX 11.34
Command "./agent_control -i [id]" return:

OSSEC HIDS agent_control. Agent information:
   Agent ID:   001
   Agent Name: agent1
   IP address: 192.168.0.2
   Status:     Active

   Operating system:    Unknown
   Client version:      Unknown
   Last keep alive:     Mon Feb 28 16:57:44 2011

   Syscheck last started  at: Mon Feb 28 01:56:42 2011
   Rootcheck last started at: Mon Feb 28 01:16:37 2011

This`s true for all agents. All other communications between agents
and server are ok.
Any advices?

Thanks in advance.